A master of the guillotine choke and leg lock submissions, Kitaoka holds notable wins over Takanori Gomi, Paul Daley, and Carlos Condit.
[5] Renowned originally for his catch wrestling abilities, Kitaoka made his professional debut for Pancrase on October 31, 2000, losing via majority decision.
After picking up two wins to start 2005, Kitaoka improved to 12-6-8 before he faced future UFC interim welterweight champion Carlos Condit on October 2, 2005.
A leg lock specialist, Kitaoka would improve to 19-7-9 before facing Katsuya Inoue on January 30, 2008 for the third time after being defeating in their first meeting and a draw in the previous bout.
[7] The win put him up against fellow Japanese fighter Eiji Mitsuoka in the tournament's semifinal taking place at World Victory Road Presents: Sengoku 6.
[1][9] In his first title defence, on August 2, 2009, at World Victory Road Presents: Sengoku 9, Kitaoka lost his lightweight championship to Mizuto Hirota.
[10] Following his title loss in Sengoku, Kitaoka returned to his home promotion Pancrase picking up wins over Jorge Rogrigues and Kuniyoshi Hironaka.
Kitaoka returned at RIZIN World Grand Prix 2017: Second Round, facing Kiichi Kunimoto in a catchweight bout of 165 lbs.
While attempting a leg lock submission on the ground, Kitaoka left himself vulnerable to a flurry of right hands from Brandao on the top, being knocked out just 1:38 into the fight.
After losing to Brandao, Kitaoka lost in his fifth defense of his DEEP Lightweight Championship to Koji Takeda via unanimous decision.
After a fairly impressive performance which included a surprising Kitoka knockdown from a left cross, Kitaoka won via split decision.
Before his fight at RIZIN 24, Kitaoka said restrictions from the COVID-19 pandemic didn't really change anything in his training camp and he simply followed the new rules about masks with ease.
[20] Kitaoka faced Yuki Takano on February 11, 2023 at DEEP 112, winning for the first time in 4 years via north-south choke in the third round.