After turning professional in 1992, John - a local lad from Wishaw - rose to prominence in the 1994/95 season when, at the age of 19, he won his first ranking tournament.
John went on to win two further ranking titles, making him the first teenager to win three ranking events in one season. By the end of the season, he had moved from 51st to 11th in the world rankings.
John is one of the most successful players in the sport's modern history, winning 28 ranking titles (16 runners-up), 17 non-ranking events and three minor-ranking events. He has won four World Championships, three UK Championships and two Masters titles.
In addition, he is one of just five players to have claimed both the World and UK Championship in the same calendar year, 1998.
In terms of world titles in the modern era, 'The Wizard of Wishaw' is fifth behind only Stephen Hendry, Steve Davis, Ray Reardon and Ronnie O'Sullivan. His 28 career ranking titles puts him in joint second place with Davis and O'Sullivan, behind Hendry.
Known as a prolific break-builder, John has compiled 659 century breaks in professional tournament play, placing him third behind O'Sullivan and Hendry, including eight competitive 147 maximum breaks.
For 16 consecutive full seasons from 1996/1997 to 2011/2012, John never fell below 6th in the world rankings, and was world number 1 on four occasions in 1998, 2007, 2009 and 2011.
John was appointed Member of the Order of the British Empire (MBE) in the 2008 New Year Honours.