made his debut on September 19, 2015 at Bellator MMA & Glory: Dynamite 1 against Mike Bronzoulis, winning via submission in the third round. In his second fight for the promotion, Thomson faced Pablo Villaseca on December 4, 2015 at Bellator 147. He won the fight via TKO in the second round. In his third fight for Bellator MMA Thomson faced Patricky Pitbull in the main event at Bellator 172. He lost the fight via knockout in the second round. On January 28, 2020, Thomson announced his retirement from mixed martial arts. Personal life Before becoming a full-time professional fighter, Thomson worked in construction. Thomson now runs and co-hosts the popular MMA and combat sports podcast "Weighing In" with legendary former MMA referee "Big" John McCarthy. Thomson made his acting debut in Fist of the Dragon (2014). Championships and accomplishments Strikeforce Strikeforce Lightweight Championship (One time) Strikeforce U.S. Lightweight Championship (One time) One successful title defense Ultimate Fighting Championship Knockout of the Night (One time) Sports Illustrated 2009 Round of the Year vs. Gilbert Melendez on December 19; Round 5 Mixed martial arts record |- | Loss | align=center| 22–9 (1) | Patricky Pitbull | KO (punch) | Bellator 172 | | align=center|2 | align=center|0:40 | San Jose, California, United States | |- | Win | align=center| 22–8 (1) | Pablo Villaseca | TKO (punches) | Bellator 147 | | align=center|2 | align=center|3:59 | San Jose, California, United States | |- | Win | align=center| 21–8 (1) | Mike Bronzoulis | Submission (arm-triangle choke) | Bellator 142: Dynamite 1 | | align=center| 3 | align=center| 0:39 | San Jose, California, United States | |- | Loss | align=center| 20–8 (1) | Tony Ferguson | Decision (unanimous) | UFC Fight Night: Mir vs. Duffee | | align=center| 3 | align=center| 5:00 | San Diego, California, United States | |- | Loss | align=center| 20–7 (1) | Bobby Green | Decision (split) | UFC on Fox: Lawler vs. Brown | | align=center| 3 | align=center| 5:00 | San Jose, California, United States | |- | Loss | align=center| 20–6 (1) | Benson Henderson | Decision (split) | UFC on Fox: Henderson vs. Thomson | | align=center| 5 | align=center| 5:00 | Chicago, Illinois, United States | |- | Win | align=center| 20–5 (1) | Nate Diaz | TKO (head kick and punches) | UFC on Fox: Henderson vs. Melendez | | align=center|