Kirk started his career with Belfast team Glentoran.
Heart of Midlothian
Having had several unsuccessful trials in England. In February 1999Jim Jefferies signed Kirk for Heart of Midlothian for £50,000. Initially viewed as an investment for the future, Kirk played in the club's U-21 side for most of his first two seasons at Tynecastle Stadium. However, in 2000–01 he firmly established himself in the first eleven, making 40 appearances and scoring 13 times. After a season decimated by injuries, he made further double-figure scoring contributions in 2002–03 and 2003–04. However, financial restraints at the Edinburgh club resulted in Kirk being released when his contract expired in the summer of 2004.
Boston United
signed Kirk for English League Two side Boston United. Kirk excelled at York Street, scoring 20 goals in little over 8 months.
Northampton Town
In March 2005 Kirk signed for Northampton Town for a £125,000 fee, signing a three and half-year contract. Despite Kirk scoring on his debut, Northampton lost to Rushden & Diamonds and a stuttering finish to the season witnessed them fall in the play-off semi-finals. The following season, Kirk's 10 goals ensured there was no repeat and Northampton gained promotion to League One. During the 2006–07 season Kirk was transfer listed alongside fellow strikers James Quinn and Scott McGleish. However, Kirk was taken off the transfer listat the beginning of the 2007–08 season and rewarded manager Stuart Gray with 3 goals in the first 3 games.
Yeovil Town
Kirk moved to Yeovil Town on 17 January 2008 for an undisclosed fee. He signed a two and a half-year contract. He scored twice in the first three games for his new club. In summer 2008 Yeovil rejected a bid from Morecambe for Kirk, though they went on to sell him to Scottish First Division team Dunfermline Athletic.
Dunfermline Athletic
In August 2008 Kirk signed a three-year contract. He made his debut coming on as a sub against First Division rivals Partick Thistle and scored his first two goals a week later against Queen of the South in a 2–1 win. Kirk has gone on to enjoy the most prolific goal-scoring period of his career with the Pars.
Alloa Athletic
In June 2013 Kirk signed with newly promoted First Division team Alloa Athletic having trained with the club in the latter part of the 2012/13 season after being released by Dunfermline due to the club being in administration.
International
Kirk has been capped 11 times by Northern Ireland. His debut came against Hungary in April 2000. After a four-year absence he played against the Czech Republic in October 2009. His most recent appearance was in a friendly against Albania in 2010. He has yet to score for his country.
