Kazuto Ioka was born in Osaka, Japan on March 24th in 1989. Ioka is listed as having won 95 fights as an amateur against just 10 losses, and after all those wins he decided to turn pro in 2009. With a record of 6-0 with 4 wins coming by knockout Ioka competed in his first world title fight winning the WBC minimumweight world title with a 5th round TKO. After two title defenses, Ioka captured the WBA minimumweight world title and moved up to the light flyweight division for his next bout.
The first fight for Ioka in his new weight class was for the vacant WBA light flyweight world title and Ioka ended the fight in the 6th round to become a 3-time world champion, winning world titles in 2 weight classes.
After 3 defenses of his light flyweight world titles Ioka moved up again, this time to flyweight. In his flyweight debut Ioka was facing Amnat Ruenroeng for the IBF flyweight world title. Ioka suffered his first loss as a pro when Ruenroeng was declared the winner via split decision. Ioka rebounded from the loss to win his next 4 fights which included winning the WBA flyweight title, his 3rd world title in 3 different weight classes, and a successful defense of that title in September of 2015.