Date of Birth: July 17th, 1967
Place of Birth: Ayrshire
Robert Thornton returned to professional darts in 2002 after several years away from the sport and qualified for the BDO World Championship for the first time in 2005. He beat Martin Atkins and Tony West before losing to his quarter-final match to Darryl Fitton. He won his first title at the Central Scotland Open in April 2007 with victory over Mike Veitch in the final.
He reached the televised stages of the 2007 Winmau World Masters and defeated Stompé, Adams and Atkins to reach the final. There he defeated Fitton by 7 sets to 5, fighting back from 5-2 behind. He won the £25,000 first prize and gained an entry to the 2008 World Championship where he again reached the quarter-finals. Victories over John Walton and Tony O'Shea were followed by defeat against the defending champion Martin Adams. Thornton won the 2008 Dutch Open in February and reached the last eight of the Scottish Open to secure a career-best WDF world rankings position of fourth place and to top the BDO rankings.
Thornton switched to the PDC in 2008 and qualified for the 2009 PDC World Championship, losing 4-3 in the second round to Wayne Mardle. He reached his first PDC final at the 2009 Players Championship Finals with victories over Mark Dudbridge, Alan Tabern, Dennis Priestley and James Wade. He was eventually beaten by Phil Taylor in the final but his performance saw a further climb in the rankings. Thornton the won two events of a PDC Pro Tour in a single weekend, claiming the Scottish Players Championship and the Scottish Regional qualifier for the UK Open. Injury and illness badly interrupted his career and he did not return until the 2012 World Championship, losing in the second round to Adrian Lewis.
In June 2012, Thornton won his second major title in the 2012 UK Open. He defeated former world champions, Mark Webster and Dennis Priestley, followed by Gary Anderson and Wes Newton to earn a place in the semi-finals. There he faced Dave Chisnall and played some of his best darts to win 10–4 and set up a meeting with Phil Taylor in the final. Thornton clinched a famous victory 11–5 and immediately rose back up to 23 in the rankings.
In October, Thornton reached the final of the 13th Players Championship, losing to Michael van Gerwen 5–6, after holding a 4-1 lead. He then defeated Gary Anderson in an all-Scottish final for the 14th event and moved on to the World Grand Prix. He defeated Mark Walsh 2–1 before beating Taylor 3-2, hitting eight maximums in the process. He was beaten by Mervyn King in the quarter-finals but reached another final in the Players Championships at the 15th event, this time losing to Peter Wright. Thornton finished second in his group in the Grand Slam of Darts but was beaten by Scott Waites in the last 16. Thornton finished 10th on the 2012 Order of Merit to qualify for the Players Championship, losing to Anderson in the second round. His UK Open victory guaranteed him a place in the Premier League for the first time.
At the 2013 World Championship Thornton scraped past Paul Nicholson in a sudden-death leg before crashing out 4-0 to Phil Taylor in the last 16.