Ikegami began drawing his first comic series at the tender age of seventeen. Even then, Ikegami had the magic touch, and his first two collaborative efforts - "AIUEO Boy" with Kazuo Koike in 1973 and Gallant Gang ("Otoko Gumi") in 1974 with Tetsu Kariya - proved so popular they set the pattern for what would turn out to be one of the manga world's biggest success stories. Although many of his earlier works were written and drawn solo, nowadays Ikegami works almost exclusively with collaborators and shows no signs of stopping.

Yayoi Neko is a fan of him.