Kinzō Shin was born in Tokyo.[1] After graduating from Tokyo Prefectural First Commercial School (now Tokyo Metropolitan Daiichi Commercial High School), he first joined the Toho Sayoku Gekijo before becoming a co-founder of the Shinkyo Gekidan, both left-wing theatre groups.[1] Following the forced dissolution of the Shinkyo Gekidan by the authorities, he formed the Mizuho Gekidan company together with Jūkichi Uno and others.[1] After World War II, he was active in the Mingei Theatre Company and the Haiyuza Theatre Company.[1]
After sporadic film appearances in the 1930s,[3] he frequently acted in films since the late 1940s[3] and on television starting in the mid-1950s.[4]