Doherty appeared in two quarter-finals in his first season as a professional, at the
1991 Classic and the
1991 Irish Masters, being beaten 5–3 by
Jimmy White on both occasions. In the following snooker year, he won the
qualifying event for the
1992 Masters, though there he lost 1–5 to
John Parrott in the first round. He also made it to the semi-finals of the 1992
British and
Strachan Open, and reached the final of the
1992 Irish Masters. He was a finalist at the
1992 Grand Prix as well, narrowly losing 10–9 to Jimmy White. In the
same event a year later, Doherty lost in the final again, this time 6–9 to
Peter Ebdon. was a semi-finalist at the
1993 International Open, and a quarter-finalist again at the
1993 Irish Masters. More quarter-final appearances followed at the
1994 Masters and the
1994 World Championship, his only run past the second round in the latter before 1997, and later on in the
1994 Dubai Classic, repeating his result from the
previous edition of the event, down to the scoreline as he was beaten 5–4 both times. These weren't his only replicated outcomes, he also won the
1994 Pontins Professional just like he did
last year, as well as the
1994 Scottish Masters In November he made it to the final of the
1994 UK Championship, which he lost 5–10 to
Stephen Hendry, then in December he reached the quarter-final stage of the
1994 European Open, where he was defeated 5–3 by
Nigel Bond. In the second half of the season, he was in yet another quarter-final at the
1995 Irish Masters, and in two finals, at the
1995 Pontins Professional and the
1995 European League. Doherty became only the third player from outside the United Kingdom (after Australian
Horace Lindrum in 1952 and Canadian
Cliff Thorburn in 1980) to win the World Championship when he beat Stephen Hendry 18–12 in the 1997 final, at the age of 27. He also reached the World Championship final in 1998, losing to
John Higgins, Doherty narrowly failed to achieve a
maximum break when he missed a routine final black off its spot in the 15th frame of the
2000 Benson & Hedges Masters final against
Matthew Stevens, a match Doherty eventually lost 10–8. This one pot would have seen him win an £80,000 sports car. However, his 140 break at least brought him the consolation of the £19,000 highest break prize. He did make a 147 break two years later though, when he won the Cue Club Pro-Am tournament in Killarney in 2002. He made light of his prize on television shortly afterwards, which was allegedly €300, a BMX bicycle and a toy
Ferrari car. His first official maximum was compiled in 2012, during a first round win against Julian Treiber at the
Paul Hunter Classic. In 2001 Doherty became one of the few players who have won back-to-back ranking events, as he won the
Welsh Open and the
Thailand Masters, while also reaching the final of the next tournament, the
Regal Scottish Open. In the 2005 World Championship, Doherty beat
Barry Pinches in the first round 10–5, winning the last 8 frames, but was knocked out in the second round by
Alan McManus 13–11. Following an average start to the
2005–06 season, Doherty won the
Malta Cup in February 2006, beating
John Higgins in the final. Doherty had trailed 8–5 at one stage but managed a stirring comeback, winning four frames in a row. He called the victory, which bridged a five-year gap, his "most important tournament win since the World Championship". Doherty started brightly in the
2006 World Championship, winning his first match by defeating
Barry Hawkins 10–1, then he beat
Matthew Stevens 13–8, playing superbly to win the last five frames. He was the favourite in his quarter-final match against
Marco Fu but lost 13–10. It was 8–8 as the final session started, but Doherty struggled despite winning a frame in which he required three snookers. Although he led 7–6, 8–7, 9–8 and 10–9, he could never quite take decisive advantage to win the match. Doherty admitted afterwards that he "blew it" but that he still had "a couple more years" to come back and win the title. He ended the 2005–06 season as the world number 2, his highest ranking ever. He made a solid start to the
2006–07 season by reaching the quarter-final at what is the closest thing to a home tournament for him, the
Northern Ireland Trophy at Belfast's Waterfront Hall. He followed this up with a last-16 defeat at the Grand Prix in Aberdeen and the UK Championship in York. He reached the quarter-finals of the next two tournaments, the Masters and the Malta Cup. He lost in the first round of the World Championship and, although clearly disappointed, the Dubliner vowed to continue. He was provisional world number 1 for most of 2006–07, but finished the season as 4th in the rankings. In October 2006, he won the invitational
Irish Professional Championship for a second time, having previously captured the title in
1993. He beat
Michael Judge 9–4 in the final. A year later he defended his title with a resounding 9–2 victory over
Fergal O'Brien. He followed this up a week later by becoming the first Irishman to win the Pot Black Invitational tournament, beating
Shaun Murphy 76–31 in the one-frame final. Doherty did not start the
2007–08 season well, winning only one match during the first four ranking tournaments. However, he did reach the semi-finals of the Masters with victories over Mark Williams and Shaun Murphy, before losing to eventual champion
Mark Selby. He then reached the final of the
Malta Cup for a record fifth time, defeating John Higgins in the semi-finals, before losing to Murphy in the final. Unfortunately for Doherty, neither of these events are ranking events, meaning his performances did nothing to keep him in the top rankings for the 2008–09 season. Defeat to
Liang Wenbo in the first round of the World Championship ensured that he dropped out of the top 16 after 15 years, and he started the new season 32nd on the provisional one-year list. A run of qualifying defeats saw him drop as low as 38th before the UK Championship. Doherty's poor run of form continued during the
2008–09 season during which he won only two matches. For the first time since 1993, he failed to qualify for the World Championship, having been beaten in the final qualifying round by
Gerard Greene. Doherty's form saw an upturn in the
2009–10 season, with a rise back into the top 32 in the rankings, up from 44th to 30th; this was due to a quarter-final appearance in the
2009 Shanghai Masters, and a last-16 appearance in the 2009 Grand Prix. Doherty defeated six-time World Championship finalist Jimmy White 10–3, and two-time Crucible semi-finalist
Joe Swail 10–1 to mark his return to the World Championship for the first time since 2008. In an amusing moment, Doherty got down on his knees and kissed the carpet upon his return to the venue. However, he lost his first-round match 10–4 to reigning Masters champion Mark Selby. The
2010–11 season proved to be a mixed campaign for Doherty, who made it to the last 32 of the
2010 World Open, yet missed out on qualifying for the
2011 German Masters, the
2011 Welsh Open and crucially, blowing a 6–3 lead, losing 10–6 to
Jimmy Robertson in the final stage of qualifying for the
2011 World Championship, meaning he had only reached the Crucible once out of his previous three attempts. Doherty had an excellent start to the
2011–12 season as he qualified for the
Australian Goldfields Open, where he reached his first ranking event semi-final since 2006. He beat Mark Selby 5–3 in the quarter-finals, sealing the match with a clearance which he described as the best of his career. Doherty also stated that he almost quit the game in 2009, following his downturn in form which saw him drop to world number 55. He failed to replicate his form in the semi-finals, however, as he was beaten 2–6 by Mark Williams. In the remainder of the season Doherty qualified for the
German Masters and the
Welsh Open, but was defeated in the first round by Williams and
Mark Allen respectively, without picking up a frame. He also reached the final of the non-ranking
Irish Classic, losing 2–5 to
Fergal O'Brien. He was ranked 32nd in the world going into the
2012 World Championship qualifiers, where he faced
Anthony Hamilton. The match went into a deciding frame with Doherty 40 points behind, but he profited from a Hamilton error to produce a match-winning clearance to win 10–9, and earned a first-round match against
Neil Robertson. He lost 4–10, and finished the season ranked world number 35. Doherty began the
2012–13 season by losing 4–5 to
Stuart Bingham in the second round of the
Wuxi Classic, and 3–5 to
Martin Gould in the first round of the
Australian Goldfields Open. He went on to reach the quarter-finals of the event, losing 0–4 to Mark Selby. Doherty was eliminated in the first round of the
German Masters by
Peter Lines, but then had his best run of the season at the
Welsh Open. He led
Stuart Bingham 2–0, but a series of missed pots saw Doherty lose his confidence and he went on to lose 3–5. His aforementioned run to the semi-finals of the Scottish Open helped him finish 16th on the PTC Order of Merit to qualify as one of the top 26 players for the
Finals, but he lost 2–4 to
Kurt Maflin in the first round. Doherty almost pulled off one of his trademark comebacks against
Matthew Selt in the final round of the
World Championship qualifying, as from 4–9 down he levelled at 9–9, but he lost the deciding frame. The result meant that this was the first season where Doherty had not featured in any of snooker's
Triple Crown events. Doherty increased his ranking by eight spots during the season to finish it ranked world number 27. Doherty qualified for all but two of the ranking events in the
2013–14 season, but couldn't advance beyond the second round in any of them. In April, he qualified for the
World Championship after a 10–5 win against
Dechawat Poomjaeng in the final qualifying round. Doherty was the oldest player in the draw in his 19th Crucible appearance, and after trailing
Stuart Bingham 5–4 in the opening session of their first round match, Doherty produced his best snooker to take all six frames in the next session and win a match at the
Crucible for the first time since 2006. He then lost 13–8 to
Alan McManus, the second oldest player in the event. Doherty won three qualifying matches and a wildcard round to be at the
2014 Shanghai Masters, where he met
Mark Selby in the first round, losing 5–2. The only other tournament Doherty could advance to the last 32 in this
season was the
2014 UK Championship by overcoming
Mitchell Mann and
Michael White, but he was beaten 6–1 by
Ricky Walden. He was knocked out of the semi-finals of the
World Seniors Championship by
Fergal O'Brien. He reached the final round of
World Championship qualifying following wins over
Reanne Evans and
Lee Walker, but was thrashed 10–3 by
Mark Davis. Doherty was placed 45th in the world rankings at the end of the season, the lowest he had been since 1991. A 6–0 thrashing at the hands of
Peter Ebdon ended Doherty's
International Championship run at the first round stage, and he lost 6–3 to
Mark Davis in the second round of the
2015 UK Championship, having whitewashed
Tony Drago 6–0 in the opener. His best results in the season were a pair of last 32 exits at the
German Masters and
Welsh Open, losing 5–1 to
Stephen Maguire and 4–2 to
Joe Perry respectively. His end of season ranking of 57 was the lowest of his 26-year professional career. He had two last 16 showings during
2016–17, and would have dropped off the tour at the end of the season as he was outside of the top 64 in the world rankings. However, the day before the
2017 World Championship started, it was announced that Doherty would receive an invitational tour card for the next two years. Doherty played against
Ronnie O'Sullivan, the defending champion, in the second round of the
2018 UK Championship. Doherty was sharp throughout the first half of the first session, leading 3–1, then he extended his lead further to 4–1, but O'Sullivan fought back to win the next 4 frames. Doherty was able to force a decider, but ultimately just one error from him was enough for his opponent to finish the frame, to prevent Doherty from causing a considerable upset in the tournament where many seeds fell to lower-ranked players already, and more would follow. Doherty would be the only player that came close to defeating the eventual champion, as the other matches, with the exception of the final, produced very one-sided results. Doherty's loss in the
2020 World Championship qualifying meant that he finished the season outside the top 64 and fell out of the tour. However, he was given an invitational tour card to continue playing professional snooker in the
2020–21 and
2021–22 seasons. The same occurred at his loss in the
2022 World Championship qualifying, for the
2022–23 and
2023–24 seasons, and at the end of the 2023–24 season, when Doherty had dropped to 79 in the world rankings, but was able to remain on the World Snooker Tour after being given a further two-year invitational card by the governing body. ==Playing style==