After the 2009 season, Gardner was signed during the off-season by
Cronulla-Sutherland Sharks coach
Ricky Stuart. Gardner explained the reasoning behind his move, stating that he moved to the Sharks to get the chance to play first-grade football. and the
Wests Tigers, although he began the season in the Toyota Cup competition. He scored a try in each of his first two games for the club against
Melbourne and
New Zealand and followed that up with four tries to help the Toyota Cup (Under-20s) team to their first victory of the season with a 22 points to 16 victory over
South Sydney. and a knee injury to
Nathan Stapleton, Gardner became the club's second debutant of the season after he played in his first first-grade match in round 10 against the
Penrith Panthers at
Toyota Stadium on 16 May. Despite eventually losing the game 34 points to 14, Gardner scored a try to help level the scores at 6-all after being set up by
Tim Smith. Gardner credited
Kade Snowden with getting him physically prepared for first-grade football and
Trent Barrett and
Paul Gallen for mentally preparing him. In the following game against his former club, the
Parramatta Eels, Gardner kicked all three of his attempted conversions in a 22 points to 18 victory. In round 13, Gardner inspired the club to a 42 points to 18 upset win against the
Sydney Roosters at the
Sydney Football Stadium. He kicked a total of 7 goals from 9 attempts and although it was his error that led to a try for
Shaun Kenny-Dowall just after the interval, he atoned for the error just under eight minutes later when he scored what many were already tipping as one of the tries of the season. After catching a
Braith Anasta bomb just under ten metres out from his own try line, Gardner sidestepped an oncoming player and then sprinted down the left-hand sideline before running across field to score in the corner of the opposite side of the field. Gardner was awarded the man of the match for his performance after notching an 18 point tally. Gardner kept up his impressive form after scoring a try and kicking 1 goal from 3 attempts in the 20 points to 19 victory over the
North Queensland Cowboys in round 16. He also scored a try in round 19 in the 48 points to 18 loss against the
Manly Sea Eagles and followed that up two games later with a try in the controversial 24 points to 22 loss against the
Wests Tigers. Two rounds later, in the round 23 match against the
Sydney Roosters, Gardner scored the match winning try which sealed an 18 points to 12 victory at Toyota Stadium. During the match he was hit high by
Frank-Paul Nu'uausala and then taken out in mid air by
Braith Anasta. Both players were placed on report following the incidents. After the match, Sharks coach
Shane Flanagan tipped Gardner as a long term fullback for the club despite believing just six months earlier that he was too small to make an impact in first grade due to his small stature. Flanagan praised his bravery by stating "he is one of the toughest players for his size I have ever seen." In the final game of the season against the
Penrith Panthers, Gardner scored another brilliant individual try again after catching a bomb just ten metres out from his own try line and running almost the length of the field to score. However, it was no more than a consolation try in a game that the Sharks would go on to lose 50 points to 12. Despite playing just 16 first-grade clubs in his debut season, Gardner finished as the club's top try scorer with eight tries. He also kicked 11 goals from 17 attempts making him joint leading point scorer for the club with
Luke Covell after finishing with a total of 54 points. He also racked up five assists for the season which put him second at the club behind
Trent Barrett. At the 2010 Dally M Awards, Gardner was nominated for the 'Rookie of the Year' but lost out to
Matt Gillett of the
Brisbane Broncos. He was also nominated for the '
Peter Frilingos Headline Moment of the Year' for his try against the
Roosters in round 13 He also polled seven points towards the
Dally M Medal. In an official NRL online poll Gardner's try against the Roosters in round 13 was voted, by fans, as try of the year. At the club's end of season awards Gardner was awarded the Steve Rogers Rookie of the Year award. Gardner has earned a reputation as one of the quickest players in the competition and was invited to race in the first ever Gatorade Bolt event which aimed to find the quickest athlete out of all the football codes in Australia. Gardner finished fourth in the race.
2011 Gardner was playing like his first season by scoring four tries in seven games. However, in round 7, Gardner struck down injured with an ankle sprain while making his well-known kick returns and being tackled and fell awkwardly. He was meant to miss out for two weeks but he returned in the next game against the South Sydney. But, he re-injured himself and missed out five weeks. He returned in round 13 against the Brisbane Broncos. But, Cronulla lost 36-16. In round 15, he scored a try and a try assist against the Bulldogs. They won that game 26-10. In Round 16, he scored two tries against the Gold Coast. They won that game 36 - 12. In round 17, he almost made another try from his well-known kick returns but couldn't go all the way. It didn't matter cause Cronulla side won that game 26 - 4. Since then, he was in good form. During the 2011 NRL finals series, Gardner required surgery on his ankle that he injured in round 7.
2014 In August 2014, Gardner was one of the Sharks players who accepted reduced bans from
ASADA under the
Sport Minister Peter Dutton for his part in the
club's 2011 supplements scandal.
2015 In 2015, Gardner spent the season playing for
Newtown in the
Intrust Super Premiership NSW. ==Wentworthville Magpies==