In January 2000 Fujita put his professional wrestling career on hiatus and began training for mixed martial arts competition. His trainer was his professional wrestling mentor and mixed martial arts legend,
Antonio Inoki, as well as luta livre veteran
Marco Ruas.
Pride and K-1 First wins Kazuyuki entered the
PRIDE organization as part of the 2000 Openweight Grand Prix. His first opponent was
Fighting Network RINGS alumnus
Hans Nijman, who Fujita beat fast by taking him down and submitting him with a wrestling neck crank. After this success, Inoki sent him abroad to compete in American promotion Extreme Shootout, where he KOed Dan Chase and then submitted Will Childs, before returning to PRIDE. On May 1, Fujita competed at
Pride Grand Prix 2000 Finals, where he would score the first big win of his career by defeating
Mark Kerr, who at the time was considered to be one of the best heavyweights in MMA. Kerr dominated early in the match, taking the Japanese down and hitting
ground and pound through his guard, followed by a series of
knee strikes to the head, but Fujita endured shockingly all the punishment and waited for his opportunity. It finally came when Kerr became visibly tired from attacking, moment in which Kazuyuki took him down, taking his back and launching his own series of knee strikes and
hammerfists. Kerr turtled up while Fujita scored points over him with unceasing striking, and at the end the referee stopped the match in Fujita's favour. His win over Kerr was considered to be a gigantic upset, and was the first loss in Kerr's career, snapping a 13-fight unbeaten streak. Fujita's next fight was against former UFC Heavyweight Champion
Mark Coleman in the semifinals of the Grand Prix, but the NJPW corner threw in the towel at the start of the match to avoid risks for Fujita's health. Despite Fujita being eliminated from the tournament, he became a star with the Japanese crowds for his victory over Kerr; the toughness he demonstrated in that fight gaining him the nickname "Ironhead". As Fujita himself noted, "I am not so great a puncher, not so great a kicker. I don't really have anything all that great, but in today's vale tudo, the strongest is the one that can take a beating." At Pride 10, Fujita next fought MMA superstar
Ken Shamrock. Like in the Kerr fight, Fujita took another incredible beating yet was not knocked out, and Shamrock then began to experience heart attack symptoms and had his corner throw in the towel, resulting in another massive win for Fujita and his career. Color commentator
Eddie Bravo proclaimed during Fujita's fight with Shamrock, "that guy can take a baseball bat to the side of the head!". He followed up his titanic wins over Kerr and Shamrock with a win over dangerous striker
Gilbert Yvel at Pride 12. Fujita scored takedowns and dominated positionally Yvel for most of the match, only occasionally trying armlocks, in order to secure a decision win. It was after this match that commentator
Stephen Quadros coined the term "lay and pray" to describe the strategy. In May 2001 at Pride 14, Fujita defeated fellow pro wrestler
Yoshihiro Takayama by submission in his first PRIDE main event. Notably, Takayama was similarly able to take a great punishment, enduring knees to the head and punches, but Kazuyuki submitted him via
arm triangle choke.
Main competition On August 19 at the K-1 Andy Hug 2001 GP Final, Fujita fought K-1 legend and future MMA legend
Mirko Cro Cop in Cro Cop's MMA debut. The fight was short and brutal, with Fujita shooting a takedown which Cro Cop tried to avoid with a knee strike to the face. Though Fujita was unfazed and completed the takedown, it opened a cut in his eye, which moved the referee to stop the match for a TKO loss for the Japanese. Fujita was baffled for the fortuitousness of the bout and requested a rematch, which was conceded for the Inoki Bom-Ba-Ye event. This fight would be longer and more intense, with Fujita repeatedly taking the kickboxer down only for the latter to successfully defend from his
guard. At the second half of the match, however, Cro Cop started dominating through
low kicks and a powerful
sprawl, which he used to hold Fujita down while scoring series of unanswered knees to the head. The bout went to the judges, where Mirko seized the unanimous win. In 2003, after Fujita defeated fellow NJPW pro wrestler
Manabu Nakanishi, he launched a challenge to PRIDE champion
Fedor Emelianenko for a match in Pride 26. When it came, Kazuyuki shocked the world by stunning Emelianenko with a heavy counter right hand, but despite his best attempts to remain on the offensive Emelianenko recovered and defeated Fujita with a
rear naked choke submission. At the end of the year, Fujita defeated American boxer:
Imamu Mayfield by submission at Inoki Bom-Ba-Ye 2003. In May 2004, Fujita made his debut for the K-1 MMA event ROMANEX, taking on then
IWGP Heavyweight Champion Bob Sapp. Not fearing Sapp's size and fame, Fujita executed a takedown and went aggressively for Sapp on the ground, repeatedly landing punches and soccer kicks on his head. At this moment, Sapp ceased fighting and only covered himself to defend Fujita's assault. Finally, the referee stopped the match for a TKO victory. Sapp had to vacate his championship after this performance, while Kazuyuki adopted the nickname of "The Real Beast" to capitalize on Sapp's own "The Beast" moniker. Egyptian Greco-Roman wrestler and Olympic gold medalist
Karam Gaber was his next opponent, at the
K-1 Premium 2004 Dynamite!! event. The younger and bigger Karam managed to push down and fend off Kazuyuki, but he landed a punch after one minute which knocked out Gaber. On May 5, 2006, at
PRIDE Total Elimination Absolute, Fujita returned to MMA by competing in PRIDE's 2006 Openweight Grand Prix making him the only fighter in PRIDE's history to have competed in both openweight grand prix. In the first round, Fujita defeated
James Thompson by knockout. Typically, Thompson dominated Fujita for most of the fight, until Fujita rallied with a flurry of punches that knocked out him at his weakest point. At the quarterfinals, Fujita fought PRIDE Middleweight champion and feared
Muay Thai striker
Wanderlei Silva. The match was wild, with Silva landing soccer kicks and knees while Fujita relentlessly tried to take him down and handle him on the ground. After avoiding
armbars and
triangle chokes by powering out, Fujita controlled the Brazilian through his guard for a few minutes, but the situation returned to the beginning when the referee stood them up. With three minutes left in the clock, Silva unloaded on Fujita and surprisingly managed to knock him down with hook combos, after which he delivered multiple soccer kicks to the face. Although Fujita was not knocked out, he was unable to stop Silva's offence, so the referee stepped in to give the Brazilian the win. After defeating freestyle champion
Eldar Kurtanidze by submission due to strikes, Fujita was pitted against
Ultimate Fighting Championship fighter
Jeff Monson. The Japanese wrestler fended off takedowns and choke attempts, but Monson was able to lock one of them to make Kazuyuki tap out. The fight was historic as it would be the final fight in PRIDE's history. Fujita would lose by submission.
World Victory Road After PRIDE was sold to
Zuffa, Fujita joined the new promotion:
World Victory Road. He debuted on March 5, 2008, at Sengoku 1 where he defeated
Peter Graham by submission. Fujita next fight was against
Travis Wiuff at Sengoku 3 where he lost by TKO. On August 2, 2009, Fujita was defeated by
Blagoi Ivanov at
World Victory Road's ninth event, Sengoku 9. On December 31, 2009, at Dynamite!! 2009, Fujita took on
Alistair Overeem and was knocked out via knee to the head in the first round. This was the first time Fujita has been knocked unconscious. After a 4-year hiatus from the sport, Fujita returned to face
Satoshi Ishii on December 31, 2013, at Inoki Bom-Ba-Ye 2013 for the
IGF Championship. Fujita lost the bout via unanimous decision, marking his fourth loss in a row.
Road Fighting Championship After an eight fight losing streak, Fujita has since competed for
Road FC where he is currently on a three fight winning streak. However, he has not competed since 2018 due to returning to professional wrestling full-time. ==Championships and accomplishments==