Biography
Seiji Miyaguchi was a Japanese stage and film actor. Born in Tokyo, he graduated from Tokyo Municipal Junior High School and co-founded the Bungakuza theatre troupe in 1937. He received the Mainichi Theater Award in 1949 for his stage work.
Miyaguchi began appearing in films from 1945. He is known for roles in Akira Kurosawa's Seven Samurai (1954) as Kyuzo, Ikiru (1952) as a yakuza boss, and Throne of Blood (1957), as well as films by directors including Yasujirō Ozu and Masaki Kobayashi. He received the Mainichi Film Concours Award for Best Supporting Actor for Seven Samurai. His later credits include the television series Shōgun (1980).
Miyaguchi died in 1985.

