Seiji Onaka was born on 15 December 1934 in Tokyo Japan. He is an actor, known for Kaijûtô no kessen: Gojira no musuko (1967), Sora no daikaijû Radon (1956) and Uzay Canavarı (1970). He has been married to Kenona since 1 May 1970. They have five children. He was previously married to Kenona.