Plymouth Argyle Mason began his career as a youth player with home-town club
Plymouth Argyle at the age of 10. He was a regular scorer for the youth team and made the step up to reserve team football with similar ease, playing his part as the club won the
Football Combination in 2009, with Mason as the club's top goalscorer. He signed his first professional contract with the club in May 2009, and immediately set about breaking into the club's first team, describing becoming a professional as a very proud moment. He began the
2009–10 season training with the first-team squad and again featured regularly for the club's reserves. He made his competitive debut, and his first start, for the club against
Sheffield United at
Home Park on 5 December 2009, playing for 65 minutes before being replaced by
Craig Noone to a standing ovation. He signed an extension to his contract with the club in January 2010 until the summer of 2012, with
Paul Mariner commenting that the youngster has a very bright future. He scored his first senior goal in the return fixture against Sheffield United at
Bramall Lane on 27 February 2010.
Cardiff City in 2013 On 8 July 2011,
Championship side
Cardiff City agreed a £250,000 transfer fee for Mason. Two days later the deal was completed and he signed a three-year deal with the Welsh club. Mason made his debut for Cardiff in a 1–0 win at
West Ham United on 7 August 2011, replacing
Craig Conway as a second-half substitute. He made his first start on 17 August in a home match against
Brighton & Hove Albion, which Cardiff lost 3–1. Mason scored his first goal for the club on 22 October, in a 5–3 victory over
Barnsley. His next goal came three days later in the
League Cup, the goal against
Burnley meant that Cardiff reached their first League Cup quarter final since 1965. Mason scored his fifth goal of the campaign in a 3–1 win at home to
Reading on 2 January 2012. Having helped Cardiff reach the
final of the
League Cup, Mason scored the first goal against
Liverpool at
Wembley Stadium on 26 February. With the score level after 90 minutes, Mason was substituted for
Filip Kiss. Cardiff lost 3–2 on penalties after the game finished two-all. Mason scored his 9th and 10th goals against fellow play-off hopefuls
Brighton and
Middlesbrough respectively, which put him in the top three goal scorers at Cardiff. On 20 April, Mason signed a new contract to extend his stay in the Welsh capital until the summer of 2016. He celebrated his contract extension with a goal against
Leeds United, then later on Mason was awarded the Club Young Player of the Year award. He enjoyed a really impressive first season in the Welsh Capital having scored 12 goals, more than he scored in his previous two put together and Cardiff had reached the play-offs but were however knocked out by
West Ham United in the semi-finals. Mason collected his first goal of the 2012–13 season on 25 August against
severnside rivals
Bristol City, which was also his 50th appearance in a Cardiff shirt. He scored his second of the season on his third league start against
Burnley on 27 October, before scoring one of City's goals in the 5–4 defeat to
Charlton Athletic soon after. His fourth came on 7 December, scoring the third in a 4–1 win at
Ewood Park against
Blackburn Rovers. Mason scored on New Years Day against
Birmingham City, which took Cardiff seven points clear at the top of the table. Mason registered his sixth goal of the 2012–13 season after coming on as a substitute against
Blackburn Rovers on 1 April 2013, at
Cardiff City Stadium.
Loans to Bolton against
Chelsea in the
League Cup in 2014 On 11 November 2013, a loan deal was agreed with
Football League Championship side
Bolton Wanderers until 5 January 2014. However, the following day it was announced that Cardiff manager Malky Mackay had a change of heart over the deal and the striker stayed in South Wales, despite having travelled up to Bolton to train with them on the previous day. A move to Bolton was finally completed on 27 November 2013 once Cardiff's injury situation had cleared up, and this allowed Mason to link up with Wanderers until the New Year on a similar arrangement to that of teammate
Kevin McNaughton. He made his Bolton debut on 30 November 2013 in an away defeat against
Middlesbrough at the
Riverside Stadium as a substitute for
Neil Danns. His first start and goal came a week later as he opened the scoring for Wanderers in a 3–0 win over
Doncaster Rovers at the
Reebok Stadium. On 20 February 2014, Mason re-joined
Bolton Wanderers on a two-month loan, but returned on 11 August 2014 for a full season-long loan. On 16 September 2014, Mason scored a second half hat-trick to earn Bolton their first win of the season at home to
Rotherham United. This was the first hat-trick scored by a Bolton player in a competitive match since
Fredi Bobic against
Ipswich in 2002. On 21 January 2015 his loan was terminated by mutual agreement.
Return to Cardiff Following his return from injury, Mason became a key part in new Cardiff boss,
Russell Slade's plans towards the end of the
2014–15 season. The next season, Mason was rewarded the number 10 shirt and started the first 17 games of the season, with a return of 5 goals. During October, Cardiff suffered a barren run of goals scoring only 2, one where Mason scored the opener in a 1–1 with
Brighton & Hove Albion. This resulted in Mason being dropped and new signing
Tony Watt taking his place.
Wolverhampton Wanderers On 28 January 2016, Mason signed a three-and-a-half-year contract with fellow Championship club
Wolverhampton Wanderers for an undisclosed fee. He made his debut for
Wolverhampton Wanderers on 2 February 2016 against Bolton, in a 2–2 draw at
Molineux, in which he scored after three minutes of the game. The following season saw him score four further goals (including against Midlands rivals Birmingham and Aston Villa), to add to the three for Wolves in the second half of the previous campaign. However, after another new head coach arrived -–the fourth different one at Wolves within his short spell – Mason found himself out of his plans. On 23 August 2017, he was sent on loan to fellow Championship side
Burton Albion until January 2018. He scored on his debut for Burton in a 1–1 draw with
Sheffield Wednesday on 26 August 2017. After returning from his spell at Burton, he moved again on loan, this time to
Major League Soccer side
Colorado Rapids on 20 February 2018 until the end of the
2018 MLS season. On 12 July 2018, it was announced that Mason would end his planned season-long loan early and return to Wolverhampton. As the 2018–19 season began in England, Mason still remained outside of the first team plans at Wolves, who had by now been promoted to the
Premier League. On 31 August 2018, he was loaned out to League One
Portsmouth until January in a move which saw him again link up with
Kenny Jackett who had signed him at Wolves. However, he made just a single appearance in the league for Pompey, appearing as a late substitute against
Wycombe Wanderers. On the final day of the January 2019 transfer window, his contract with Wolves was terminated by mutual agreement to allow Mason to find a new permanent club.
Milton Keynes Dons On 4 June 2019, Mason joined newly promoted League One club
Milton Keynes Dons. Having suffered another injury setback early in the season, Mason's appearances for the club were limited and at the conclusion of the
2019–20 campaign he was one of nine players released. Mason re-joined the club in August 2020 ahead of the
2020–21 season. On 19 January 2021, Mason scored a 28-minute
hat-trick in a 3–1 home win over
Fleetwood Town.
Cavalry FC On 10 May 2021, Mason signed a multi-year deal with
Canadian Premier League side
Cavalry FC. He made his debut for Cavalry on 18 July against the
HFX Wanderers. In his third game for Cavalry on 3 August, Mason scored his first goal for the club, netting the first goal in a 2-1 comeback victory over
Albertan rivals
FC Edmonton. In January 2022, it was announced Mason would return for the 2022 season, his second with the club. After two seasons Mason would be the leading goal scorer for the club. In January 2023, Cavalry announced they had exercised Mason's contract option for the 2023 season. Upon completion of the 2023 season, Mason would be out of contract, ending his time with the club. During his final season he helped them win the
2023 CPL Shield. ==International career==