Celtic McGowan came through the
youth system at
Celtic, at which time he was considered primarily to be a
striker.
Loan to Greenock Morton McGowan was loaned out to
Greenock Morton for the
2006–07 season. He played as a striker for Morton and scored a total of 16 goals in 44 competitive matches. During his spell at
Cappielow, McGowan won the
Scottish Football League's
young player of the month award for January 2007. He was the club's top scorer and received a winner's medal as Morton won the
Scottish Second Division. He was chosen to the 'Team of the year' in the Second Division and 3rd place in the 'Player of the Year' award. Morton failed to land the player in the summer transfer window when their bid – approaching a six-figure sum – was rejected.
Return to Celtic McGowan made his Celtic debut in a 5–0 win over
Inverness Caledonian Thistle in September 2007, where he came on as a substitute. It was his only appearance of the season. He scored his first goal for Celtic on 7 August 2008 in a pre-season
friendly against
Manchester City at
Celtic Park. He had the chance to score another to win the match, but his shot hit the crossbar and the game ended 1–1. McGowan made his
UEFA Champions League debut against
Villarreal on 10 December 2008, as a 75th-minute substitute for
Aiden McGeady. Celtic won the match 2–0 but finished bottom of their group, and once again McGowan did not appear for the club again during that campaign. and started his first game with an assist for
Chris Swailes in the 1–0 win over
Ross County in the
Scottish Cup. His first goal for the club came on 21 February 2009 in a 2–1 win over
Falkirk, scoring from 10 yards out. At the end of the 2008–09 season, his loan spell came to an end.
Return to Celtic In the 2009–10 season, McGowan became part of the Celtic first team squad under manager
Tony Mowbray. On 17 December 2009, just over a year to the day of his European bow, McGowan made his
Europa League debut in a 3–3 draw away to
Rapid Vienna; he made an impact in the 91st minute by scoring his first competitive goal for the
Hoops to complete a comeback from 3–0 down to draw 3–3. On 24 January 2010, McGowan made an impressive display when he provided assists for both
Marc-Antoine Fortuné and
Paddy McCourt, as Celtic made a comeback from 1–0 down to win 4–1 against
St Johnstone. On 29 April 2010, he signed a two-year contract with Celtic. Having signed the new deal, McGowan stated in May 2010 that he expected to make more appearances in the first team in the near future, but in fact he had already made his final appearance for the club the previous week. He made his league debut for the club in the opening game of the 2010–11 season, a 1–1 draw against
Dundee United on 14 August 2010. He scored his first competitive goal for the
Buddies in a
Scottish League Cup match against
Ross County – St Mirren lost in the penalty-shootout when the tie ended 2–2 after normal time and 3–3 after extra-time. In September 2010, McGowan received a straight red card for an off-the-ball violent incident involving
Manuel Pascali of
Kilmarnock, which was spotted by the referee. He was then observed to make a rude hand gesture at opposing fans who had been taunting him. After the match, McGowan apologised for his actions, while his manager
Danny Lennon stated a fine would be considered once video evidence had been reviewed. After missing one game, he made his return from suspension on 25 September and scored his first goal, in a 2–1 loss against
Inverness Caledonian Thistle. In January 2011, McGowan scored the first
hat-trick of his career in a 6–1 win over
Peterhead in a fourth round replay in the
Scottish Cup. Lennon described McGowan as a "threat", who needed to rise above difficult treatment, advising him to learn from the attitude of
Lionel Messi. Throughout the season, he played a total of 39 matches and scored 6 goals in all competitions for St Mirren. Danny Lennon converted McGowan from a
striker to a central attacking midfielder with the role of
playmaker during this period.
Permanent move to St Mirren On 6 June 2011, McGowan signed a two-year deal with St Mirren, having had a successful loan spell. McGowan's first game after signing for the club on a permanent basis came on the opening game of the season, in a 0–0 draw against
Dunfermline Athletic. In a 2–0 loss against his former club, on 28 August 2011, McGowan made a mistake when he misplaced a pass, allowing
Gary Hooper to score, but Lennon praised him in spite of this, while McGowan himself stated he would take full responsibility for his performance. He scored a brace in a 3–0 victory against Kilmarnock in September 2011, and netted two more on 22 October 2011 in a 3–2 loss against
Hibernian. In November 2011, McGowan attracted interest from English clubs, believed to be
Crystal Palace and
Wigan. He won the
Scottish Premier League player of the month award for December 2011. McGowan revealed he was surprised to receive the award, and was the first
Saints player to win it since
Andy Dorman in April 2009. McGowan gained plaudits for his ability to retain possession of the ball. Throughout the season, he played a total of 45 matches and scored 8 goals in all competitions for St Mirren. After scoring two goals at the outset of the 2012–13 season (in a 5–1 win over
Ayr United in first round of the Scottish League Cup, and in a 3–1 loss against
Kilmarnock on 22 September 2012), McGowan suffered a shoulder injury that required surgery. While on the sideline, captain
Jim Goodwin stated the club missed McGowan he was a major player. McGowan returned to the first team in mid-Decemberand went on to score a penalty against former employers Celtic in the
Scottish League Cup semi-final; St Mirren qualified for the final with an unexpected 3–2 win. Ahead of the
2013 Scottish League Cup Final, McGowan scored and provided an assist for
Graham Carey in a 2–0 league win over
Heart of Midlothian, and in the showpiece event itself at
Hampden Park, he was named 'man of the match' in the
Buddies 3–2 victory over the same opposition as the club ended its 26-year wait for silverware. After the match, McGowan told
BBC Scotland that he felt "very proud". A few weeks after the final, McGowan scored a penalty in a 1–1 draw against Celtic. Towards the end of the 2012–13 season, McGowan admitted that his future was uncertain, having attracted interest from English clubs, with one believed to be
Birmingham City after manager Lennon revealed he had yet to sort out his future at the club by signing a new deal. Eventually, on 3 June 2013, it was announced that McGowan had re-signed for St Mirren on a free transfer, just two days after his previous contract had expired. After signing a new contract, he cited family reasons as his basis for staying in
Paisley. In the 2013–14 season, McGowan started off his season by struggling to score for the eight games, netting his first of the season on 5 October 2013, in a 2–0 win over Hearts. He scored another, as well as two assists, in a 4–3 win over
St Johnstone on 19 October. In the match against
Inverness Caledonian Thistle, McGowan limped off where he sustained a broken toe, and later had to wear a protective mask in the
fourth round replay of the Scottish Cup against
Queen of the South. Despite being disciplined by the club for an incident away from football, and the other against Hibernian on 19 April 2014, to help the club secure their future in the Scottish Premiership. After the latter match, McGowan stated he was happy to put the disciplinary incident behind him by helping the club finish the season on a high. At the end of season 2013–14, St Mirren announced that McGowan would not be offered a new contract and he was released.
Dundee McGowan signed a two-year contract with newly promoted side
Dundee in June 2014. Upon joining Dundee, Manager
Paul Hartley stated he immediately sought to signed him once he learned he was released by St Mirren. McGowan made his Dundee debut, playing as a central midfielder, as Dundee won 4–0 against Peterhead on 2 August 2014 in the
Scottish League Cup, and then made his league debut as Dundee drew 1–1 with Kilmarnock on 9 August 2014. McGowan continued to be in the first team throughout the first half of the season until he suffered a knee injury that kept him sidelined for four weeks. He made his return to the first team in the
Dundee derby, which Dundee lost 6–2 to
Dundee United. McGowan scored his first Dundee goal in the last minute in a 1–0 win over
Partick Thistle on 14 February 2015. As a result of being placed on a court-imposed curfew for another incident outside football, During a League Cup group stage match against
Forfar Athletic in 2016, McGowan chipped
Grant Adam on the edge of the box to open the scoring in a 7–0 win for Dundee. He then scored in the opening league game of the
2016–17 season, a 3–1 win over
Ross County in
Dingwall, however afterwards Dundee would go into a six-game losing streak which saw the club involved in a relegation fight. On 29 October, McGowan scored a crucial winning goal in a 1–0 victory over Hamilton. Just before Christmas he scored an equalising goal against Hearts as Dundee came from 2–0 down to win 3–2. Towards the end of the season McGowan assisted
Marcus Haber to score in a crucial match against
Kilmarnock in a 1–0 win to help Dundee steer clear of relegation during
Neil McCann's reign as interim manager. McGowan scored his first goal of the
2017–18 season against
Dundee United in the
Dundee Derby to win the game 2–1, beating
Harry Lewis from 20 yards. He picked up his second goal of the season with another long-range strike in a 1–1 draw with
Motherwell at
Fir Park. While not netting for the rest of the season, McGowan was a key player in once again keeping the Dee in the Premiership. After
St Johnstone manager
Tommy Wright confirmed his interest in signing him, McGowan signed a new one-year contract extension with Dundee with the option of a further year. McGowan remained an important piece in the
2018–19 season, but had to endure a horrible season where the club managed just five league wins all season, and only one of them being at home, en route to relegation. Despite the dismal season, McGowan managed a couple of league goals during the season, both against
Hibernian. The first was a crucial equaliser at
Easter Road in November during Dundee's most successful spell of the season, and the second also being an equaliser at Dens, though Dundee would eventually lose the game. As the
2019–20 season began, McGowan was given the captain's armband many times, and scored two key penalties in shootouts during Dundee's
League Cup group stage matches to help them top the group. McGowan would get his scoring underway in his 200th appearance for the club, scoring the opener against
Partick Thistle, though a late Dundee collapse would ruin the day. He went on to score the next week, away to
Ayr United with what would prove to be the game-winning goal in a 2–1 victory. McGowan would next find the net on 14 December, scoring against
Dunfermline Athletic in a 4–3 victory, and followed that up with his second goal in as many games the next week, once again netting against Partick in an away win. McGowan continued being a key player for the Dark Blues until the season was ended early due to the
COVID-19 pandemic. After the season was brought to a close, McGowan was named the winner of the Andrew De Vries Player of the Year Award for the 2019–20 season. As one of the Dundee players due to have his contract expire in June and with many club officials and players on furlough due to the pandemic, McGowan's contract was extended until July in order to give more time for discussions. McGowan signed a one-year extension with Dundee near the end of June 2020, agreeing to drop his wages significantly for the year to help the club cope better with the coronavirus crisis. In April 2021, an appearance clause in his contract triggered a further one-year extension in McGowan's contract, keeping him with Dundee until the summer of 2022. He would play a prominent role in Dundee's success in the
Premiership play-offs, and helped the club gain promotion back to the Premiership. In January 2022, McGowan would once again agree a one-year contract extension, taking him into his ninth season with the club. McGowan would mark his 300th appearance for the
Dark Blues in September 2022, in what would be his first for the club outside of Scotland as Dundee defeated Welsh champions
The New Saints away in the
Scottish Challenge Cup. He would spend several months out with a knee injury.
Loan to Dunfermline Athletic On 21 February 2023, McGowan reunited with former teammate and manager
James McPake after joining
Scottish League One club
Dunfermline Athletic on loan until the end of the season. On 25 February, McGowan made his debut for the
Pars as a substitute in an away league win against
Queen of the South. He would win the Scottish League One with Dunfermline on 15 April 2023, in a 5–0 home win against Queen of the South. McGowan would score his first goal for the
Pars in their final game of the season on 6 May in an away win against
Alloa Athletic. On 1 June 2023, Dundee would confirm that McGowan had left the club after the completion of his contract.
Cove Rangers On 24 July 2023, McGowan joined
Scottish League One club
Cove Rangers on a one-year deal. He made his debut in a
Scottish League Cup group stage match against
Livingston. McGowan scored his first goal for Cove Rangers on his 36th birthday in a win against
Annan Athletic. At the end of the season, Cove confirmed that McGowan would leave upon the expiry of his contract.
Annan Athletic On 27 June 2024, McGowan joined
Scottish League One club
Annan Athletic. McGowan made his debut for the
Galabankies in a win over
Inverness Caledonian Thistle in the
Scottish League Cup group stage. McGowan scored his first goal for Annan three days later against
Bonnyrigg Rose. On 14 September, McGowan grabbed his first league goal of the season with a last-minute equaliser at home to
Dumbarton. On 6 June 2025 after Annan's relegation to
Scottish League Two, McGowan agreed a one-year extension to remain at
Galabank. ==Personal life==