2003 Slater started playing for the
Melbourne Storm in
2003. In Round 1 of the
2003 NRL season, Slater made his first-grade
NRL debut for the
Melbourne Storm against the
Cronulla-Sutherland Sharks at
Remondis Stadium. Slater started on the and scored a try in Melbourne's 36–32 win after overcoming a 22–0 deficit early in the first half. In Slater's next match in Round 2 against the
Penrith Panthers, Slater played his first match for the Storm at , scoring 2 tries in the Storm's 42–16 win at
Olympic Park. From Rounds 4–8, Slater played in the centre position before moving back to fullback in Round 10 against the
Brisbane Broncos in the Storms 36–16 loss at
Queensland Sport and Athletics Centre. Slater played the rest of the year at fullback. After a stellar début season saw him crowned Dally M Rookie of the Year (although the awards that year were cancelled in protest), Slater was the Storm's highest try scorer in the
2003 NRL season with 19 tries in their 26 matches.
2004 Slater made his debut on the for Queensland in game one of the
2004 State of Origin series. Slater had a quiet but solid first game in QLD's 9–8 loss at
ANZ Stadium. Slater retained his spot on the team for the second game of the series at
Suncorp Stadium. In game two, just days shy of his 21st birthday, Slater was named man of the match after scoring two tries. His second try is considered one of the great individual Origin tries. Trailing 12–10, Slater latched onto a grubber kick from
Darren Lockyer, chip-kicked the ball over Blues fullback
Anthony Minichiello, regathering the ball and scoring in QLD's 22–18 win. Slater scored a try in the decider but could not stop a
Brad Fittler inspired
New South Wales side from clinching the series in QLD's 36–14 loss. Slater's club form helped his team finish 6th on the ladder, defeating the
Brisbane Broncos 31–14 at
Suncorp Stadium in the first game of the finals before succumbing to eventual premiers the
Canterbury-Bankstown Bulldogs 43–18 at
SFS. Slater played 22 matches and scored 14 tries for the
Storm in the
2004 NRL season. He was named in the
Kangaroo squad to tour Europe but injury prevented him from joining in the tour.
2005 Slater once again impressed in his third NRL season. Once again he was picked for the Queensland State of Origin team, this time at his preferred position of fullback. Slater returned for the second game in Sydney which saw the return of
Andrew Johns, who spearheaded a New South Wales victory. Despite losing the match 32–22, Slater took advantage of a knock-on from the Blues
Anthony Minichiello to score a length of the field try during the match. Slater was dumped from the Queensland side for the deciding third game in Brisbane which led to outrage from some Maroons fans. With injuries and suspensions, Slater had to wait three years for another chance at State of Origin. Slater continued his brilliant form throughout 2005, topping the try scoring charts with 20 tries in 21 matches for the
Storm. Melbourne once again finished 6th in the league and defeated the
Brisbane Broncos 24–18 at
Suncorp Stadium in the first game of the finals before missing the Storms 24–16 season ending loss succumbing to an in-form
North Queensland Cowboys team at
SFS.
2006 Slater had a less successful 2006 season. Slater was suspended in Round 4 for seven matches for kicking
Wests Tigers prop
John Skandalis, but also scored two tries in the match. Injuries and suspensions kept Slater out of contention for a spot in the Queensland team in 2006. In his comeback game in Round 13 against the
Sydney Roosters in the Storms 20–16 win at
Olympic Park, Slater only played 25 minutes of the second half on the wing and was later found guilty of using a dangerous throw on Roosters centre
Ryan Cross. Slater was suspended for 2 matches. After Slater's second suspension, Melbourne Storm coach
Craig Bellamy decided to give Slater some warm up matches for his comeback into first grade with both
North Sydney Bears (Melbourne's feeder club in the
NSWRL Premier League) and
Norths Devils (Melbourne's feeder club in the
Queensland Cup). Slater made his NRL comeback in Round 18 playing his preferred fullback position when the Storm defeated the
Brisbane Broncos 10–4 at
Olympic Park. In Round 22 against the
Wests Tigers in the Storms 46–4 win at
Olympic Park, Slater was given a two match suspension for a late forearm, which was his third suspension for the season. Slater came back to the main line-up in Round 25 against the
Canberra Raiders in the Storms 22–18 win at
Canberra Stadium. A few weeks later, after having claimed the minor premiership the Storm again met the
Brisbane Broncos, this time in the
2006 NRL Grand Final. It was Slater's first and he played at fullback in what was Melbourne's first grand final loss after succumbing 15–8 to a Broncos team in Melbourne player Scott Hill farewell NRL match before moving to the ESL. Slater played in 15 matches and scored 5 tries for the
Storm in the
2006 NRL season.
2007 Slater had a quiet start to the 2007 season. In Round 8, he suffered a badly broken cheekbone against the
Manly-Warringah Sea Eagles when he tried to charge down former teammate
Matt Orford's kick, and collided with teammate
Sam Tagataese in Melbourne's 13–12 loss at
Brookvale Oval. On his return from injury in Round 17, Slater scored 8 tries from 9 appearances and became a vital cog in the back line of the Storm, setting up over 20 tries during the season. In Round 21 against the
Cronulla-Sutherland Sharks at
Remondis Stadium, Slater played his 100th
NRL career match in the Storms 17–16 win. Slater was part of the Melbourne Storm
2007 NRL Grand Final winning team at , defeating the
Manly-Warringah Sea Eagles 34–8, which was later stripped from them for cheating the salary cap. Slater played in 23 matches and scored 12 tries for the
Storm in the
2007 NRL season. Slater won the Storms Back of the Year Award. In the post season Slater was named at in the
Melbourne Storm Team of the Decade.
2008 Slater's start to the 2008 season can be described as nothing short of sensational. He scored 3 tries in Melbourne's 32–18 Round 1 win at
Etihad Stadium, one at
SFS in Round 3, a 10–6 loss to the
Sydney Roosters and two at
Olympic Park in Melbourne's 26–4 win over the
Manly-Warringah Sea Eagles. After his start to the season, Slater garnered praise from league experts such as
Laurie Daley and
Andrew Johns as being the best player in the game. Slater's form was rewarded when he was selected at fullback for the
Australian national team in the Centenary Test against
New Zealand, displacing the incumbent
Brett Stewart. Slater had a modest game in attack for Australia but proved his worth by making numerous try-saving tackles in Australia's 28–12 victory at
SCG. Two weeks later, Slater was selected to once again represent Queensland in the
2008 State of Origin series, this time displacing incumbent,
Karmichael Hunt from fullback to five-eighth, Slater had a mixed performance for Queensland throwing a few loose passes despite running over 220 metres and making a line break that nearly resulted in a try to
Greg Inglis. Queensland eventually lost, 18–10. Slater returned for Game 2 but was dropped to the interchange bench before replacing
Karmichael Hunt 30 minutes into the match at
ANZ Stadium. In Game 2 Slater played off the interchange bench in QLD's 30–0 win in Brisbane. In Game 3, Slater once again started from the interchange bench with
Karmichael Hunt starting at fullback. A broken arm to Scott Prince at the 17-minute mark forced Slater to fullback with
Karmichael Hunt switching to five eighth. Slater broke the line with his first touch and kick return of the game. He was excellent under the high ball, thwarting many attacking kicks. With just 10 minutes to go,
Johnathan Thurston broke the New South Wales line, drawing in the fullback before passing the ball to Slater who ran the remaining 30 metres to score the match-winning try and a 16–10 victory. It was Slater's first series win for Queensland. In Round 19, Slater was involved in an all-in brawl in a match against the
St George Illawarra Dragons in the Storms 26–0 win at Olympic Park. He was sin-binned for throwing several punches at winger,
Jason Nightingale. He had a two-match suspension downgraded to one match after claiming Nightingale had provoked him with several head-butts throughout the match. In August 2008, Slater was named in the
preliminary 46-man Kangaroos squad for the
2008 World Cup. In September 2008; Slater narrowly missed out on the Dally M Medal, Player of the Year, finishing 2 points behind the
Sea Eagles Matt Orford. The one-week suspension in Round 19 deducted 3 points from Slater's tally, which would have won him the medal. Days after playing in the
2008 NRL Grand Final 40–0 defeat the
Manly-Warringah Sea Eagles, Slater was named the Melbourne club's Player of the Year. Slater played in 24 matches and scored 14 tries for the
Storm in the
2008 NRL season. Slater capped off a brilliant year by winning the
Rugby League World Golden Boot Award as the best player in the world. In 2008, he also received the Rugby League International Federation's International Player of the Year award. . In October 2008, Slater was selected in the final 24-man
Australian squad but hesitated playing since he and his wife were expecting their first child. Slater went on to play fullback for Australia in the 2008 World Cup, scoring hat-tricks in matches against England (52–4 win at Etihad) & Fiji (52–0 win at the Sydney Football Stadium). Slater won the Man of the match twice in tournament for his performance in both games. About midway through the second half of the World Cup final Slater, who had set up Australia's first two tries, made a grave misjudgement, Slater threw a wild pass back in field after attempting to go the short side from a kick return and it was snapped up by
Benji Marshall for a gift four-pointer. Although Melbourne teammate
Greg Inglis bought them back within 2 points with a try, a penalty try, courtesy of a
Joel Monaghan infringement, ruled out any possible comeback. Despite his costly error and Australia losing the game 34–20 to
New Zealand, Slater was named
Player of the Tournament following the World Cup final in
Brisbane. Slater was also the competition's top tryscorer with 7 tries.
2009 Slater was selected for
Australia in the
2009 Anzac Test match at against
New Zealand at
Suncorp Stadium in the Kangaroos' 38–10 redemption win over the Kiwis. In April 2009, he was named in the preliminary 25-man squad to represent Queensland in the opening State of Origin match for 2009, and was subsequently picked at fullback for the opening State of Origin match. Slater was the first try scorer in the 2009 State of Origin Series scoring in Queensland's 28–18 win in Sydney. Slater played in the other 2 matches in the Queensland's 2009 winning State of Origin team. In Round 22 against the
North Queensland Cowboys at
Olympic Park, Slater played 150th NRL career match in the Storms 20–8 win. Melbourne finished the season 4th on the NRL table and avenged their 2008 Grand Final loss to
Manly by defeating them 40–12 in the first week of the finals at
Etihad Stadium. Slater's four try haul earned him man of the match honours. Slater notched up his 100th
NRL career try in Melbourne's 40–10 victory over the
Brisbane Broncos in the preliminary final at
Etihad Stadium, becoming only the second Melbourne player to do so after
Matt Geyer. . In the next week, the Grand Final was won by the
Melbourne Storm over the
Parramatta Eels 23–16. Again this was also stripped from Melbourne for systematic salary cap cheating. Slater scored a try and was judged best on ground, earning the Clive Churchill Medal. Slater was named the Storms highest tryscorer in the
2009 NRL season with 18 tries in 26 matches. During the off-season he was given the first 'Player of the Finals' award, presented by the Rugby League Writers' Association. Slater topped off the season with selection for Australia in the
2009 Four Nations tournament in Europe. Slater played in the first two matches against New Zealand and then England. Slater scored three tries in Australia's 46–16 win over
England in the final and also acrobatically tapped the ball back infield setting up a try for teammate,
Cameron Smith.
2010 For the
2010 Anzac Test, Slater was selected to play for
Australia at in their 12–8 victory against
New Zealand at
AAMI Park. Despite Melbourne being stripped of their 2007 and 2009 premierships due to the
discovery of a salary cap breach, Slater was allowed to keep his Clive Churchill Medal. Slater was also involved in Queensland's 3–0 whitewash in the
2010 State of Origin series and received the Wally Lewis Medal for player of the series. In the third match, he saved a certain try, before scoring the match-turning and winning try with five minutes remaining in Queensland's 23–18 win in Sydney. Slater played in 22 matches and scored 10 tries in the Storms drama filled
2010 NRL season in which they were stripped all premiership points, and barred from collecting anymore (Including ones earned from byes) on 22 April as a result of their
salary cap breach 2011 In Round 2 against the
Gold Coast Titans at
AAMI Park the Storms 40–12 win, Slater scored two where he broke the record for the number of tries scored for
Melbourne Storm with 114 tries, previously held by
Matt Geyer with 113 tries. For the
2011 Anzac Test, Slater was selected to play for
Australia at , scoring two tries in the Kangaroos 20–10 victory against
New Zealand at
Cbus Super Stadium. Slater played in all three
2011 State of Origin matches, as for the Queensland Maroons. Slater scored in the last 10 minutes of Game 1 in the Queensland's 16–12 win in
Brisbane, and scored in the last 15 minutes of Game 3 in QLD's 34–24 series winning match in
Brisbane. In Round 24 against the
St George Illawarra Dragons at
AAMI Park, Slater played his 200th
NRL career match in the Storms 8–6 win. The
Melbourne Storm won the minor premiership, but were defeated by the
New Zealand Warriors 20–12 in the Preliminary Final at
AAMI Park, ending Slater's season. Slater was awarded the 2011 Dally M Medal for best and fairest player of the year in the NRL. Following the awarding of the Dally M Medal, there was commentary about Slater's progress. Sports reporters Ray Warren said that he "didn't think Slater was as good a player as he had been in the past", while
Andrew Johns labelled Slater as "the best fullback he has seen". After playing in 24 matches, Slater was the Storms joint highest tryscorer with 12 tries alongside
Cooper Cronk and
Matt Duffie in the
2011 NRL season. On 3 October, Slater was selected for the
Australian Kangaroos, to play as in the
2011 Rugby League Four Nations tournament. While on tour, Slater was named the Rugby League International Federation's International Player of the Year for the second time. Slater suffered a collarbone injury and was ruled out of the tournament after
Australia's 36–20 win over
England at
Wembley Stadium. Slater played in 3 matches of the series.
2012 Slater started the year scoring 9 tries in 5 games, including 2 tries per game in the opening 4 rounds of the season. For the
Anzac Test, Slater was selected to play at fullback in the Kangaroos 20–12 victory against
New Zealand at
Eden Park. Slater was Queensland's fullback for Games 1 and 2 of the
2012 State of Origin series which saw the Maroons record winning streak extend to seven series. Slater finished the
2012 NRL season with him scoring 16 tries in 21 matches for the
Storm, which made him the highest fullback try scorer in the NRL with 140 tries, going past previous holder
Rhys Wesser with 129. Slater scored a try in Melbourne's 14–4 premiership victory over
Canterbury-Bankstown Bulldogs, where Slater was bitten in the ear by
James Graham during a scuffle. Slater was selected at for the Kangaroos October Test against
New Zealand at
1300SMILES Stadium. The Kangaroos won the match 18–10. An established ambassador for
Adidas, in 2012 Slater appeared as part of a promotional campaign for their F50 adizero III boots alongside
Dale Thomas of Aussie Rules and European football (soccer) player
David Villa.
2013 Slater scored the first try in Melbourne's
2013 World Club Challenge 18–14 win over
Leeds Rhinos. In the
2013 Anzac Test, Slater played at for
Australia in the Kangaroos' 32–12 victory against
New Zealand at
Canberra Stadium. Slater played all three games of the
2013 State of Origin series in which Queensland extended their record for consecutive series victories to eight. In Round 21 against the
Canberra Raiders at
Canberra Stadium, Slater also became the 8th player in history of the League to score 150 tries, Slater scoring 2 tries in the Storms 68–4 win. Slater was the
Storm's highest tryscorer in the
2013 NRL season with 18 tries in 24 matches. In the post season, Slater was chosen in
Australian 24-man squad for the
2013 World Cup which Australia won the Final against
New Zealand 34–2 at
Old Trafford, where Slater scored 2 tries. Slater played in 4 matches and scored 4 tries in the tournament.
2014 In Round 2 against the
Penrith Panthers, Slater reached a milestone of having played 250 games for
Melbourne Storm in the 18–17 win at
AAMI Park. In the
2014 Anzac Test, Slater played at for
Australia in the Kangaroos' 30–18 victory against
New Zealand at
SFS. Slater played all three games of the
2014 State of Origin series in which Queensland lost the series 2–1, the first series the NSW Blues won since the 2005 series. In Round 22 against the
Newcastle Knights in the Storms 32–30 loss at Hunter Stadium, Slater eclipsed
Andrew Ettingshausen tryscoring record with 166 tries, Slater now currently being third in the highest tryscorer ranks. Slater finished the
Storm's
2014 NRL season with him playing in 22 matches and scoring 12 tries.
2015 Slater started the 2015 season, playing featuring in the first 5 rounds of the season. He picked up a shoulder injury in the Storm's 30–14 home game win over the
Warriors, which resulted him missing the next 4 weeks of action; including the
Kangaroos' Annual Trans-Tasman
ANZAC Test match clash to the
Kiwis, with
Greg Inglis filling his Fullback position. He returned to action in round 8, producing a strong 80-minutes man-of-the-match performance against the
Parramatta Eels, scoring 2 tries and producing a try-saving tackle on
Semi Radradra. Carrying a shoulder injury (not 100% fully recovered) from the Storm's Round 5 game (in April) that resulted him being ruled out the Trans-Tasman
ANZAC Test, Slater featured for
Queensland in Game 1 and Game 2 of the
2015 State of Origin series. After the Storms' Round 10 match against the
South Sydney Rabbitohs in the 16–12 win at
AAMI Park and following game 2 of the
2015 State of Origin series at the
Melbourne Cricket Ground, Slater was ruled out of Origin Game 3 (the decider) and for the rest of the
2015 NRL season due to him having surgery on his troublesome injured shoulder (he originally injured in April, in Round 5). Slater's incumbent fullback position was filled by
Greg Inglis for Queensland for game 3 of the Origin Decider, while
Cameron Munster who had a stellar year for the Storm filled his Fullback position for the Storm. Slater finished the season with him only playing in 7 matches and scoring 2 tries for the Storm. Slater was a late withdrawn from the Storm's round 2 clash against the Titans and after having an arthroscope, he was then later again ruled out for 6–8 months as well as for the season; after pulling up sore following the Storm's victory over the Dragons. With speculations surrounding his playing future following that shoulder reconstruction, his
Melbourne Storm Fullback role was filled again by
Cameron Munster. During his time on the sideline, his Fullback positions was filled by
Darius Boyd for both
Australia (during the International Trans-Tasman
ANZAC Test match, which was played at Newcastle's
Hunter Stadium) and
Queensland (for the
State of Origin Series). Despite still being out of action, he missed being part of
Queensland's
State of Origin victorious campaign although he worked closely with new Maroons coach
Kevin Walters as a consultant during the
2016 State of Origin series period, assisting him in coaching and working with the backs, as well as working closely with the team. Slater also missed being part of
Storm's
Grand Final home-away-from-home clash to the
Cronulla Sharks and
Australia's successful
Four Nations campaign, as well as missing the first ever
Perth International Rugby League Trans-Tasman
Test match. At the end of the 2016 season, Slater was awarded (and received) the Peter Jackson Medal for his outstanding contribution in assisting
Kevin Walters with the coaching during the
2016 State of Origin series for
Queensland.
2017 Slater was set to return to action in the Storm's trial match clash against the
Canterbury-Bankstown Bulldogs at
North Hobart Oval in
Hobart, Tasmania. However, coach
Craig Bellamy opted to rest him for the opening 2 rounds of the 2017 season and Slater had to wait until round 3 to returning to action. In Round 3, Slater made his successful return against the
Brisbane Broncos at
AAMI Park, starting from the bench and playing for 52 minutes in the Storm's 14–12 win. The following week, he started at Fullback in the Storm's 22–14 win over the
West Tigers playing 80 minutes at
Leichhardt Oval, which was his first full-game and away game. In Round 9, Slater finally broke his long try-scoring drought by scoring 2 tries in a strong man-of-the-match performance in the Storm's 34–22 win over the Dragons. This was the first time he scored a double of tries, since round 9 of the 2015 season. Despite playing consistently well since coming back from injury; Slater was left out of the
Australian Kangaroos Test Squad for the International Trans-Tasman
ANZAC Test match to
New Zealand, with coach
Mal Meninga opted to stay loyal and stick with
Darius Boyd at Fullback, as well as the players who were part of last year's successful
Four Nations Campaign. Playing his first game in his home state of
Queensland in over 1000 days and since round 4 of the 2015 season (which was against the
Cowboys at
1300SMILES Stadium in
Townsville) in the NRL Indigenous Round and the Round 10 double-header at
Suncorp Stadium; Slater continued his consistent form by producing an outstanding performance scoring a try, setting-up 2 tries, making 8 tackles, 16 runs (174 metres), 2 line-breaks and a line-break assist; despite the Storm narrowly losing 36–38 to the
Titans. This was also his first game playing at
Suncorp Stadium, since round 20 of the
2014 Season which was against the
Brisbane Broncos; despite missing Game 3 (the decider) of the
2015 State of Origin series and last year's Game 2 of the
2016 State of Origin series. With
Greg Inglis already sidelined and ruled out of the season with a season-ending knee injury, Slater was expected to return to the
Queensland Squad for the
2017 State of Origin series. Despite this, coach
Kevin Walters opted to stick with
Darius Boyd at Fullback, keep
Justin O'Neill at right centre,
Corey Oates at left wing,
Dane Gagai at right wing and bring in
Will Chambers to play left centre; which resulted him being controversially left out of the Game 1 Squad. Following
Queensland's Origin Game 1 loss to
New South Wales, Slater continued-on with his outstanding consistent performances helping the Storm to victories over the
Knights and
Sharks. He was then recalled to the
Queensland squad along with
Johnathan Thurston for game 2, which resulted incumbent
Australian Test Fullback
Darius Boyd shifting to Centre and
Justin O'Neill dropped from the team. In Game 2 of the Origin Series, Slater produced an outstanding performance setting-up 2 tries (the first try of the game to debutant left winger
Valentine Holmes, when he combined with
Johnathan Thurston and
Darius Boyd; and the game-winning try to right winger
Dane Gagai, when he combined with
Michael Morgan leading-up to
Johnathan Thurston kicking that winning conversion goal) helping QLD to level the series margin to 1-all in the 18–16 win over NSW at ANZ Stadium. Slater remained in the team for game 3 and he produced another outstanding performance in the decider, combining with Storm teammates
Cameron Smith,
Cooper Cronk and
Cameron Munster in QLD's NRL one-club spine combination; to guide QLD to a series win in the 22–6 victory over NSW at
Suncorp Stadium. Playing his first NRL final series appearance since 2014 (despite missing the 2015 and 2016 play-offs due to shoulder injuries) and during the first week of the NRL play-offs final series; Slater played a key part in his side's 18–16 win over the
Parramatta Eels at
AAMI Park, scoring a try (his 180th NRL career try) in the 2nd half of the game which resulted him drawing level to former
Manly Sea Eagles player
Steve Menzies as the game's all-time second-equal highest top try-scorer. With the Storm fresh off their break (after Week 2 of the NRL Final Series) and after their 18–16 victory over the
Parramatta Eels (in the first week of the Final Series), Slater featured in the club's Grand Final qualifier match against the
Brisbane Broncos scoring 2 tries (both in the second half – the 59th minute and in the 71st minute) in the 30–0 win, allowing the Storm progressing through to the Grand Final and resulted him to move past
Steve Menzies as the game's stand-alone second highest top try-scorer (behind another former
Manly Sea Eagles player
Ken Irvine, who had scored 212 tries). On 27 September leading into the
Grand Final; Slater was awarded the Fullback of the Year Award at the NRL Dally M Awards Event. Playing in the
Grand Final at
ANZ Stadium on 1 October; Slater produced an outstanding performance guiding the
Melbourne Storm to win the 2017 NRL Premiership (their first Premiership since 2012), beating the
North Queensland Cowboys 34–6. Following the game, he received the
Clive Churchill Medal as the best player on the field. Two days following the
Grand Final victory, Slater was named in the
Australian Test Squad for the
2017 Rugby League World Cup Tournament. He also signed a one-year extension, committing to the
Melbourne Storm for the 2018 season. Playing at Fullback in his first international test match for
Australia since 2014, Slater scored a try and produced an outstanding man-of-the-match performance in the 18–4 win over
England at Melbourne's AAMI Park. The following week, he equaled the record of
Bob Fulton and
Jarryd Hayne in becoming the Tournament's Top Try-Scorer in
Rugby League World Cup history by producing another outstanding performance and scoring his 13th
World Cup try (his 24th Test-Career Try) in Australia's 52–6 win over
France in Canberra. Coach
Mal Meninga opted to rest Slater for the
Lebanon clash in Sydney, leading into the play-offs. Slater then returned to the starting line-up at Fullback for the quarter-final game, scoring a try in Australia's 46–0 win against
Samoa in Darwin. He then played in Australia's semi-final game against
Fiji, scoring 2 tries (which resulted him breaking the all-time World Cup Try-Scoring Record; scoring his 16th World Cup try, as well as his 27th Test try) in the 52–6 win at
Suncorp Stadium, guiding the Australians to the World Cup Grand Final. Playing Fullback in the World Cup Grand Final at
Suncorp Stadium, Slater featured in Australia's 6–0 win over England, playing an important role and producing another fine performance in the green-and-gold jersey.
2018 Slater started the season, sitting out of the Round 1 game (to the Bulldogs in Perth) due to injury. He returned to the field in Round 2, playing his 300th NRL Career game in the 8–10 loss the
West Tigers at
AAMI Park. Slater earned criticism during a home Round 6 game against the Newcastle Knights where he was accused of diving which led second-rower
Lachlan Fitzgibbon to be
sin-binned. While Slater had the right to go for a quick-tap because he was outside the 10-metre, many disapproved when Fitzgibbon stuck out his hand out on shoulder lightly to make Slater hit the deck. Both fans and social media users were questioning the physics of Slater falling, thus drawing accusations of diving. Slater also captained the
Melbourne Storm for the first time in his NRL Career and during
Cameron Smith's suspension absence, against the
Manly Sea Eagles in the 4–24 loss during Round 11. Slater announced his intentions to retire from representative football after the 2018 State of Origin series and was yet to make a decision on playing only at the club level in 2019. Slater was set to play in the opening game of the Origin series at the
MCG; however, he withdrew from the Game 1 squad due to a
hamstring injury, in what would have been his last Origin match in Melbourne. He returned from injury in game 2 to play his 30th Origin game, producing an outstanding performance despite Queensland losing game 2 and the series in New South Wales' home game victory at
ANZ Stadium. Following an injury to Queensland teammate and captain
Greg Inglis, Slater was named captain for game 3 in his final Origin game. Producing yet another outstanding performance, Slater led Queensland to an 18–12 victory at
Suncorp Stadium, thus avoiding a potential 3–0 series whitewash by New South Wales. For his efforts, Slater received the Wally Lewis Medal for Player of the Series, despite having only participated in two of the three Origin games and Queensland's overall series loss. On 8 August, Slater announced that he would be retiring from the NRL at the end of the 2018 season. He played his final game, a grand final loss to the Sydney Roosters, on 30 September 2018. ==Post-playing career==