Born in Claremont, Western Australia, Missingham was educated at Perth Boys' School, and later undertook an apprenticeship to the process engraver J. Gibney and Son in 1922.

Before World War II he studied in Perth, Paris and London, where he became friendly with a number of leading artists and developed an interest in photography.

He returned to Sydney in 1941 and after serving as a Signalman in the Second Australian Imperial Force helped to found the Studio of Realist Art.

His collection policy made an outstanding contribution to Australian contemporary art and he was responsible for bringing a number of influential international exhibitions to the country.

His memoirs, They Kill You in the End, were published in 1971[3][4] Missingham was the longest serving director of the gallery until Edmund Capon.