Despite losing his first seven wrestling matches, Mir went on to win the state heavyweight wrestling title in 1998.
He faced Ian Freeman, at UFC 38: Brawl at the Hall, held in London, England on July 13, 2002. Despite several leglock attempts by Mir, Freeman achieved side control at around four minutes into the first round, landing numerous elbows and punches on Mir's head. After Freeman separated, the referee signaled an exhausted Mir to stand back up. A time out was called due to an apparent cut on Mir's face, and the referee stopped the fight when a wobbly Mir had difficulty standing up.
On June 26, 2003 Mir fought Wes Sims at UFC 43: Meltdown. Mir won by disqualification at 2:55 of round one after Sims stomped down on Mir's face after slamming his way out of Mir's armbar attempt. They would rematch at UFC 46: Supernatural on January 31, 2004. Frank Mir won by knockout at 4:21 of round two.
An interim heavyweight title was created whilst Mir was recovering from the injury, which Andrei Arlovski won. On August 12, 2005, UFC learned that Mir was not able to fight Andrei Arlovski in October as scheduled, thus Mir was stripped of the title after 14 months, and Arlovski was promoted to the undisputed UFC heavyweight champion.
Mir returned to the Octagon on July 8, 2006 at UFC 61: Bitter Rivals and faced Dan Christison. Mir had gained a considerable amount of weight since his last appearance and quickly became exhausted. Mir won by unanimous decision after three rounds, the judges all scored the bout 29-28. Mir next faced Brandon Vera at UFC 65: Bad Intentions. Mir was unable to mount any significant offense against Vera, and lost by TKO at 1:09 of the first round.
Mir fought Renato Sobral in a special submission grappling superfight at a Tuff-N-Uff event named "Unarmed Combat" that had a six minute time limit on June 22 2007. Sobral won the bout by points (6-2).
Mir fought Brock Lesnar at UFC 81 on February 2, 2008. Early in the first round, Lesnar took Mir down and, while striking from Mir's guard, landed an illegal punch to the back of Mir's head, drawing a foul and a one-point deduction from referee Steve Mazzagatti. They were stood up and Mir was given a brief recovery period, but Lesnar quickly took Mir down again. When Lesnar escaped an armbar attempt, Mir caught him with a kneebar, causing Lesnar to tap out at 1:30 of the first round.
The season, which premiers on Spike TV on Sept. 17, will return to the two-weight class format. It features light heavyweight and lightweight fighters. Production on season eight begins in late May, with the entire cast to be announced in September.
Nogueira and Mir, after serving as coaches, will meet at UFC 92 for Nogueira's UFC Interim Heavyweight Championship. The fight will take place December 27th in Las Vegas, Mir's home town.
|Win||Brock Lesnar||Submission (kneebar)||UFC 81: Breaking Point||February 2, 2008||1||1:30||Las Vegas, Nevada, United States|
|Win||Antoni Hardonk||Submission (kimura)||UFC 74: Respect||August 25, 2007||1||1:17||Las Vegas, Nevada, United States|
|Loss||Brandon Vera||TKO (strikes)||UFC 65: Bad Intentions||November 18, 2006||1||1:09||Sacramento, California, United States|
|Win||Dan Christison||Decision (unanimous)||UFC 61: Bitter Rivals||July 8, 2006||3||5:00||Las Vegas, Nevada, United States|
|Loss||Marcio Cruz||TKO (strikes)||UFC 57: Liddell vs. Couture 3||February 4, 2006||1||4:10||Las Vegas, Nevada, United States||First fight after the motorcycle accident.|
|Win||Tim Sylvia||Technical Submission (armbar which caused a radial fracture)||UFC 48: Payback||June 19, 2004||1||0:50||Las Vegas, Nevada, United States||Fight was for vacant UFC heavyweight title.|
|Win||Wes Sims||KO (strikes)||UFC 46: Supernatural||January 31, 2004||2||4:21||Las Vegas, Nevada, United States|
|Win||Wes Sims||DQ (stomping the head of a downed opponent)||UFC 43: Meltdown||June 6, 2003||1||2:55||Las Vegas, Nevada, United States|
|Win||Tank Abbott||Submission (toe hold)||UFC 41: Onslaught||February 28, 2003||1||0:46||Atlantic City, New Jersey, United States|
|Loss||Ian Freeman||TKO||UFC 38: Brawl at the Hall||July 13, 2002||1||4:35||London, England|
|Win||Pete Williams||Submission (shoulder lock)||UFC 36: Worlds Collide||March 22, 2002||1||0:46||Las Vegas, Nevada, United States|
|Win||Roberto Traven||Submission (armbar)||UFC 34: High Voltage||November 2, 2001||1||1:05||Las Vegas, Nevada, United States||Mir's UFC Debut.|
|Win||Dan Quinn||Submission (triangle choke)||IFC Warriors Challenge 15||August 31, 2001||1||2:15||Oroville, California, United States|
|Win||Jerome Smith||Decision (unanimous)||HOOKnSHOOT-Showdown||July 14, 2001||2||5:00||Evansville, Indiana, United States||Mir's MMA Debut.|