In submission wrestling, Kerr is a four-time ADCC World Champion, winning his weightclass twice along with the absolute division and the Superfight Championship.
In 2002, Kerr was the subject of an HBO documentary titled The Smashing Machine, which detailed his MMA career fighting in Vale Tudo, the UFC and PRIDE.
The Smashing Machine also focused on Kerr's struggle with substance abuse, his relationships with his then-girlfriend, various training partners, and friendship with Mark Coleman.
[13] From early childhood, he would dream of being in the World Wrestling Federation and would hold mock fights with his younger siblings in the back yard.
He, his long-time friend and training partner Mark Coleman and Tom Erikson were initially scouted by Richard Hamilton, who had managed Ultimate Fighting Championship fighter Don Frye until a falling out and was now offering a place in UFC 10 against him.
[18][19] Eventually, Kerr and Hamilton arranged for the former to train with Coleman and fight at the Brazilian event World Vale Tudo Championship 3 in January 1997.
His appearance was highly anticipated, as other wrestlers like Coleman or Erikson were already known in the MMA community, though there were doubts about Kerr's true skills.
[20][13] Kerr himself was doubtful about it, to the point Hamilton had to force him to fight under the threat the Brazilian crowd might riot and kill him if he didn't show up.
The bout lasted two minutes, with Kerr slamming Varelans with a takedown, mounting him and landing punches and knee strikes for the stoppage.
[20] The same happened to his next opponent, Mestre Hulk, a capoeira police teacher who had become known for besting Brazilian jiu-jitsu fighter Amaury Bitteti.
Advancing to the finals, Kerr fought Dwayne Cason and finished his opponent within the first minute of the opening round, winning the UFC 15 Heavyweight tournament.
Kerr was said to be an improved version of Mark Coleman[citation needed] because he was proficient in wrestling, submissions, and take downs, with good cardio and an ever-improving striking game under his tutelage with Bas Rutten.
His win against Inoue earned him a place at the Pride Grand Prix 2000 Finals, where he fought Kazuyuki Fujita and lost by decision.
[citation needed] Mark Kerr fought in the World Cage Fighting Organization (WCO) in November 2007, winning his bout against Steve Gavin by Americana after 1:39 of the first round.
Two months later, Kerr was choked out in the opening round by deaf fighter Tracy Willis at a C-3 Fights show in Cocho, Oklahoma.
Kerr was taken down and subsequently pounded into unconsciousness in just 25 seconds, receiving several blows to the head after he was clearly unable to defend himself.
At the 1999 tournament, he won the +99 kg division by defeating Carlos Barreto, Josh Barnett, Chris Haseman, and Sean Alvarez.
[28][29] In 2002, HBO aired a documentary titled The Smashing Machine, directed by John Hyams, which dealt with the life and career of Mark Kerr.
The program chronicles Kerr's addiction to painkillers and the "no holds barred" aspect of early mixed martial arts competition.
Kerr's then-girlfriend, Dawn Staples, and mixed-martial artists Bas Rutten, Kevin Randleman and Mark Coleman also appear in the film.
Bas Rutten states clearly during the documentary that due to Kerr's ability to end fights quickly, the Pride tournament directors were removing all of Kerr's 'weapons' (notably head-butts and knees to the head of a grounded opponent) in an attempt to make the fights last longer for television and crowd satisfaction.