[1] He appeared in more than 200 films between 1935 and 1988, directed by notable filmmakers such as Kenji Mizoguchi, Mikio Naruse, Keisuke Kinoshita and Kaneto Shindō.

[2][3] After leaving high school prematurely, Ozawa started acting in the left-wing theatre groups Toho Sayoku Gekijo and Shinkyo Gekidan.

[2] In 1940, the authorities ordered the dissolution of the Shinkyo Gekidan and arrested many of its members, including Ozawa, who was forced to change his stage name Sakae to his real name Eitarō.

[1] After the war, he returned to the Haiyuza and started appearing in films again such as Yasujirō Ozu's Record of a Tenement Gentleman (1947), Akira Kurosawa's Scandal (1950) and Mizoguchi's Ugetsu (1953) and The Crucified Lovers (1954).

[1] In addition to acting, Ozawa was active as a director of stage plays, including Bertolt Brecht's The Good Person of Szechwan which he had seen performed in Berlin,[4] and as a writer.