Luke Stewart has trained and competed in Brazilian jiu-jitsu for several years, and is a black belt under Ralph Gracie, in San Francisco, California.

[2] Stewart made his professional mixed martial arts debut in 2006, signing with now-defunct promotion Strikeforce in May 2006.

[7] In his fifth fight with the promotion, Stewart faced Bryson Kamaka at Strikeforce: Four Men Enter, One Man Survives on November 16, 2007.

[10] Despite being a considerable betting favorite coming into the bout, Stewart lost the fight via unanimous decision, the first loss of his professional MMA career.

After a one-year hiatus from MMA, Stewart returned to face André Galvão at Strikeforce Challengers: Johnson vs. Mahe on March 26, 2010.