Strikeforce (2006–2010) Stewart made his professional mixed martial arts debut in 2006, signing with now-defunct promotion
Strikeforce in May 2006. He made his debut facing Bill Duvall at
Strikeforce: Revenge on June 9, 2006. He won the fight via armbar submission, 1:15 into the first round. In his second fight with the promotion, Stewart faced Jeremiah Metcalf at
Strikeforce: Tank vs. Buentello on October 7, 2006. He won the fight via rear-naked choke. He then faced
UFC veteran
Jason Von Flue at
Strikeforce: Shamrock vs. Baroni on June 22, 2007. He won the fight via third round TKO. Stewart faced Sam Liera at
Strikeforce: Playboy Mansion on September 29, 2007. He won the fight via first round TKO. In his fifth fight with the promotion, Stewart faced Bryson Kamaka at
Strikeforce: Four Men Enter, One Man Survives on November 16, 2007. He won the fight via knockout, just 19 seconds into the first round. In his next fight, he faced
Tiki Ghosn at
Strikeforce: Shamrock vs. Le on March 29, 2008. 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. Stewart faced
Jesse Juarez at
Strikeforce: At The Mansion II on September 20, 2008. He won the fight via first round armbar.
Joe Riggs at
Strikeforce: Destruction on November 21, 2008. He lost the fight via second round TKO. After a one-year hiatus from MMA, Stewart returned to face
André Galvão at
Strikeforce Challengers: Johnson vs. Mahe on March 26, 2010. He lost the fight via split decision, and subsequently retired from mixed martial arts shortly after. ==Personal life==