Having turned professional in 1991, King was ranked within the world’s top 32 players between 1996 and 2015, and won his first ranking event title in 2016, defeating Barry Hawkins 9–8 in the final of the Northern Ireland Open. He has also appeared in two other ranking tournament finals: the 1997 Welsh Open, where he lost 2–9 to Stephen Hendry; and the 2004 Irish Masters, where Peter Ebdon defeated him 10–7.
King has reached the last 16 of the World Championship seven times, in 1998, 1999, 2001, 2002, 2008, 2009 and 2013.
1997: Reaches his first ranking final at the Welsh Open, knocking out Steve Davis and Mark Williams before being denied the title by Stephen Hendry.
2002: Climbs to 11th in the world, his highest ranking.
2004: Runner-up to Peter Ebdon at the Irish Masters, having beaten Stephen Hendry, Jimmy White and Ken Doherty to reach the final. His only Triple Crown semi-final appearance comes at the UK Championship where his run is ended by Stephen Maguire.
2013: Reaches the last 16 of the World Championship for the seventh time, beating Mark Allen at the Crucible before losing to Ding Junhui.
2016: Wins his first ranking title at the Northern Ireland Open in Belfast, coming from 5-1 down to edge out Barry Hawkins 9-8 in the final. Emotional victory speech gives him the Magic Moment of the Year award.
2018: Semi-finalist at the European Masters.