[2] He made his BDO World Championship debut at the 2008 edition, eliminating 10th seed Martin Atkins in the first round.

[6] Later that year, he claimed the Granite City Open title in Aberdeen by beating former world champion John Walton in the final.

[7] Boulton suffered first-round defeats at the 2011 and 2012 BDO World Championships, losing to Robbie Green and Scott Waites.

[12] He was drawn into Group E with Gary Anderson, Raymond van Barneveld and Larry Butler, but failed to win a match.

[17] He returned to Alexandra Palace at the 2020 PDC World Championship, but was defeated 3–2 by debutant Danny Baggish in the first round.

[22][23] On 16 March 2024, Boulton claimed two Challenge Tour titles on the same day, winning events 8 and 9.