He is the founder and head trainer at AMC Pankration in Seattle which is home to UFC flyweight champion Demetrious Johnson, ONE FC interim bantamweight champion Bibiano Fernandes and he has trained numerous world class fighters including Josh Barnett, Bob Sapp, Chris Leben, Hayato Sakurai, Akira Shoji, Matt Brown, Rich Franklin, Mario Miranda and Caros Fodor.
Kojima made his debut at the organization with a submission win over Filipino Rey Docyogen at ONE FC: Return of Warriors at Putra Indoor Stadium in Kuala Lumpur on February 2nd.