Suit-actor and martial artist, holding a second degree black belt in karate. He became a frequent collaborator and choreographer of monster fights with premiere suit actor Haruo Nakajima, acting opposite Nakajima in Godzilla vs. the Sea Monster (1966, as Ebirah), War of the Gargantuas (1966, as Sanda), King Kong Escapes (1967, as Gorosaurus and Mechani-Kong), and Destroy All Monsters (1968, as Anguirus and Gorosaurus again). He also briefly played Godzilla in Son of Godzilla (1967), after baseball star and intended suit actor Seiji Onaka broke his hand between takes. Nakajima held Sekida in the highest esteem out of all the suit actors he’d worked with.