Growing up, Kato pursued judo but favored the striking techniques of traditional Japanese martial arts such as karate.
He later returned to his martial arts roots at the age of 23, joining the Kudo Federation of Japan where he competed and won five consecutive national tournaments.
After winning his fifth title, Kato was offered a contract by the Japanese MMA promotion HEAT.
He compiled a 4–1 record, which included a first-round TKO of Yuki Niimura to win the vacant Heat Middleweight Championship.
Kato faced Joe Schilling in his promotional and United States debut at Bellator 139 on June 26, 2015.
[3] Despite being a sizable underdog, Kato won the bout in highlight-reel fashion, knocking out the seasoned kickboxer with a superman punch early in the second round.
[5] Kato faced another experienced kickboxer, Melvin Manhoef, at Bellator 146 on November 20, 2015, in the main event.
Despite Schilling being the more experienced kickboxer, Kato again won the fight by knockout due to a spinning back fist in the second round.
[21] Kato faced Ryo Aitaka at K-1: K'Festa 5 on April 3, 2022, in the reserve bout of the 2022 K-1 openweight tournament.