[1][2] After graduating from the law department at the University of Tokyo, he worked as an assistant director at the Daiei Film studio.

[1] The following year, he won a scholarship allowing him to study film in Italy at the Centro Sperimentale di Cinematografia under Michelangelo Antonioni, Federico Fellini and Luchino Visconti.

From 1955, he worked as a second-unit director on films directed by Kenji Mizoguchi, Kon Ichikawa and Daisuke Ito.

[4] In 1957, he directed his own first film Kisses,[4] which caused film critic (and future director) Nagisa Ōshima to note, "a powerful irresistible force has arrived in Japanese Cinema.

[6] According to film critic Shigehiko Hasumi, filmmaker Shinji Aoyama had declared Masumura "the most important filmmaker in the history of postwar Japanese cinema.