[2] He was beaten in the semi-finals of the Eastbourne Open in 2003 and 2004 and reached the first final of his career at the Golden Harvest North American Cup, but lost 4–0 to John Part.
[5] His first semi-final in a major event was at the 2005 Las Vegas Desert Classic where he knocked out George Walls, Mark Walsh and Ray Carver, before losing 4–0 to Phil Taylor.
[6] Newton suffered a broken collarbone by slipping in the shower shortly after the event which kept him out of action for three months but returned to play in his first World Grand Prix, losing 3–0 in the second round to Colin Lloyd.
[9] He reached the semi-finals of the Las Vegas Desert Classic for the second successive year but was denied a place in the final as John Part beat him 4–2.
[12] In June, at a Players Championship event at Hayling Island he reached his first final on the PDC Pro Tour but was whitewashed 3–0 by Terry Jenkins.
At the Grand Slam, he was knocked out in the group stage after defeating Michael van Gerwen and losing to Ted Hankey and Phil Taylor.
Newton continued his progress at the 2011 World Championship, defeating Darin Young, Brendan Dolan and Mensur Suljović on the way to the quarter-finals.
In March 2011, Newton moved into the top eight of the PDC Order of Merit, following a win in a Pro Tour event in Crawley.
Newton breezed through the first round of the 2012 World Championship by whitewashing Kurt van de Rijck 3–0 and played Justin Pipe in the last 32.
He also beat Kevin Dowling, Andy Brown, Robert Thornton, Jerry Hendriks and Richie Howson on the way to the final.
[24] At the World Matchplay, Newton beat James Hubbard 10–5 in the first round,[25] before throwing the first televised nine-dart finish of his career in the 11th leg of his last 16 match against Justin Pipe.
[26] He beat Tomas Seyler, Kevin Painter and then Andy Hamilton in the quarter-finals to face his room-mate Brendan Dolan in the semis.
[26] At the World Grand Prix, he was a dart away from exiting the tournament in the first round to Ronnie Baxter, but his opponent missed and Newton went on to win 2–1 in sets, before beating Ian White 3–1 in the last 16.
[33] Newton topped Group G in the Grand Slam of Darts with wins over Martin Phillips, Wesley Harms and Terry Jenkins to face BDO player Christian Kist in the last 16.
[35] After all 33 ProTour events of 2012 had been played, Newton finished seventh on the Order of Merit to qualify for the Players Championship Finals where he lost to Gary Anderson 4–6 in the first round.
[46] He reached the final of the fifth Players Championship by beating Michael van Gerwen 6–4 in the semi-finals, but lost 6–1 to Peter Wright.
The match went into a deciding set with Newton losing it 5–3 in legs to bow out of the event via a 5–4 defeat in the quarter-finals for the third time in four years.
[55] His season did finish on a positive note at the Players Championship Finals when he knocked out Justin Pipe 6–1, Brendan Dolan and Terry Jenkins both 10–5, before succumbing to an 11–6 defeat against Adrian Lewis in the semi-finals.
[56] Newton lost the first two sets against qualifier Cristo Reyes in the opening round of the 2015 World Championship, but rallied to level at 2–2.
The deciding set went to a sudden-death leg which Reyes won to produce a result referred to as one of the biggest upsets in the tournament's history.
Both players were visibly irritated by the mistake and Newton posted a series of angry Twitter messages after the match, although he accepted that Reyes deserved to win.
[61] In a rematch from last year, Newton drew Cristo Reyes in the first round of the 2016 World Championship and won the first set despite averaging just 67.31.