His father, Minoru Okada, was an artist and his mother, Ingeborg Sevaldsen, was the sister of Eline Eriksen, the model for the "Mermaid of Copenhagen".

The elder Okada was an associate of Chaïm Soutine who moved to Nice from Paris, and was oft patronized by Kunio Kishida.

He signed with Nikkatsu Corporation in 1954, appearing in his first film, "Hatsukoi Kanariya Musume"/"Canary Girl's First Love", the following year.

This performance led to his appearance in the companion film, "Kurutta Kajitsu"/"Crazed Fruit" (1956), in which he played the cool, laid-back, finger-snapping Amerasian, "Frank Hirosawa", the unofficial leader of a band of young "rebels without a cause".

His credits include all genres in the three media—from stage musicals to horror films, from comedies to historicals to tragedies, and from Shakespeare to science-fiction.

He acted as the French physicist, "Dr. Jules Masson", in Ishiro Honda's "Latitude Zero"/"Ido Zero Daisakusen"/"Atragon II" (1969).

Okada's film credits also included "Arashi wo yobu otoko"/"Man Who Causes a Storm" (1957), "Akai hatoba"/"Red Quay" (1958), "Ankoku no Ryoken"/"Passport to Darkness" (1959), "Yoru no nagare"/"Evening Storm" (1960), "Oneechan wa tsuiteru ze"/"Anything Goes Three Dolls' Way" (1960), "Kyuketsu Dokurosen"/"Living Skeleton" (1968), "Moeru Tairiku"/"The Blazing Continent" (1968), "Isoge!

Tomorrow Never Waits" (1974), "Hishu monogatari"/"A Tale of Sorrow and Sadness" (1977), "Fuku no hana"/"Winter's Flower" (1978), "Umi to dokuyaku"/"The Sea and Poison" (1986), "CF Garu"/"Commercial Film Girl" (1989), "The Hunted" (1995), "Izo" (2004) and "Shiberia Chotokkyu 5"/"Siberia Express 5" (2005).

In 2001, he appeared as the French philosopher and writer, Voltaire, in a Japanese-language version of the operetta, "Candide", by Leonard Bernstein, the composer of "West Side Story" (1957).

"The Space Giants", "Latitude Zero", "Marco", "Shogun" and "The Hunted" were some of his credits which became international hits, and brought him into contact with actors such as Joseph Cotten, Richard Jaeckel and Cesar Romero ("Latitude Zero"), Desi Arnaz Jr. and Zero Mostel ("Marco"), Richard Chamberlain and John Rhys-Davies ("Shogun") and Christopher Lambert ("The Hunted").

Again, his ability to speak fluent Japanese, English and French proved to be an asset, as were his powerful, deep and sensuous vocals.

Masumi Okada was appointed as one of Japan's Ambassadors to the Hans Christian Andersen 2005 bicentenary, a list of events organized in celebration of the nineteenth-century Danish author's life and works.

In 1960, he announced his two-year "contractual marriage" to the renowned dancer and mime choreographer, Mamako Yoneyama—a union which ended even before the first year was over.

Then, on July 27, 2004, Okada's third son with Fujita was found hanged at his mother's home in the Denenchofu suburb of Tokyo.