Hamilton is a four-time World Championship quarter-finalist, a Masters semi-finalist and he has compiled more than 300 century breaks during his long career.

In 1997 he reached the second round; facing John Parrott at this stage he scored 414 unanswered points in frames 1–5, but still lost the match (this is the second-highest number of unanswered points in Crucible history; the record was set by John Higgins against Hamilton in the second round in 2000).

[6] Hamilton's best result of the season came at the Welsh Open, where he reached the quarter-finals by defeating both Joe Perry and Dave Harold, before losing his match to Steve Davis in a final-frame decider.

[15] He could qualify for the televised stage of the 2007 UK Championship, by defeating Barry Pinches 9–6, but lost against Mark Selby 5–9 in the first round.

He lost in the first round 3–5 against Andrew Higginson at the Northern Ireland Trophy,[20] 2–5 against Marco Fu at the Shanghai Masters,[21] and 0–5 against John Higgins at the Grand Prix,[22][23] while he could not qualify for the Bahrain Championship and the UK Championship, as he lost in the qualifying round 2–5 against Mark Davis and 4–9 against Higginson respectively.

[12] In 2009–10 season Hamilton couldn't qualify for the first two ranking events, as he lost 0–5 against Jamie Cope at the Shanghai Masters,[30] and 0–5 against David Gilbert at the Grand Prix.

[35] In 2010/2011 season Hamilton failed to qualify for the first three ranking events as he lost 2–5 against Ricky Walden at the Shanghai Masters, 1–3 against James McBain at the World Open and 3–9 against Rod Lawler at the UK Championship.

[36] Hamilton also participated in all Players Tour Championship events, with his best performance coming at the Paul Hunter Classic, where he reached the final, but lost 3–4 against Judd Trump.

[36] Hamilton finished 18th on the Players Tour Championship Order of Merit and qualified for the Finals,[37] where he lost 0–4 against Mark Williams in the second round.

[39] Hamilton finished 42nd on the Players Tour Championship Order of Merit, outside of the top 24 who qualified for the Finals.

[41] He could not qualify for the first four ranking events, as he lost 4–5 against Michael White at the Wuxi Classic, 3–5 against Jimmy Robertson at the Shanghai Masters, 3–6 against Ryan Day at the International Championship and withdrew from the Australian Goldfields Open.

[42] Hamilton played in nine of the ten Players Tour Championship events this season, with his best result coming in the Kay Suzanne Memorial Trophy, where he defeated George Marter, Ryan Causton, Andrew Higginson, Michael Wasley and Mark Selby, before losing 3–4 to John Higgins in the semi-finals.

[49] At the venue he defeated Ryan Day, Stuart Bingham and Mark Williams to reach the quarter-final, where he lost 3–5 against Robert Milkins.

[50] After this, Hamilton failed to qualify for two of the next three ranking events; he lost 2–5 against Mark Joyce at the Shanghai Masters,[51] and 3–6 against Paul Davison at the International Championship.

[63] This performance helped him to finish 23rd on the European Tour Order of Merit,[64][65] and qualified for the Finals, where he reached the last 16, but lost 3–4 against Gerard Greene, despite leading 3–0.

[77] Hamilton finished his season by reaching the final qualifying round for the World Championship, but was edged out 10–9 by Robbie Williams for the Crucible place.

[80] Hamilton reached the quarter-finals of the English Open by beating Jak Jones 4–3, but lost 5–2 to Liang Wenbo.

[87] From starting the season with no ranking points he finished it 25th in the world, 31 places ahead of the next newly qualified player, Yan Bingtao.

[88] Hamilton beat Sam Craigie 6–3 and Scott Donaldson 10–5 to qualify for the 2020 World Championship but then withdrew from the tournament.

Being an asthmatic, Hamilton had criticised the decision to allow a limited number of spectators into the Crucible in the midst of the coronavirus pandemic.

Defending champion Judd Trump said Hamilton should have made his decision earlier because, by participating in the qualifiers despite knowing there would be spectators in the final stages, he had denied a place to another player.

[93] In 2001 he suffered a broken wrist while attempting to come to the rescue of a friend who was mugged in a nightclub,[94] an injury which kept him out of three tournaments and ultimately cost him his place in the top 16 of the 2001/2002 season.