Distinguished looking, left-leaning actor who came to the screen in 1948 after considerable experience as an actor/director on the Chicago and Broadway stage. During the "Red Scare", Wanamaker appeared in "Give Us This Day" (1949), directed in London by Edward Dmytryk, a blacklisted member of the Hollywood Ten and after appearing in another film in England remained there to avoid any possible repercussions for his political commitments. After appearing in two British productions, however, he found that the tentacles of the Hollywood blacklist reached across the Atlantic, making it impossible for him to continue working in film.

Wanamaker subsequently made a name for himself as an actor, director and producer of Shakespeare and contemporary fare on the British stage and founded the Globe Playhouse Trust. He returned to the USA in 1961 and resumed his screen career with notable performances as the Russian agent in "The Spy Who Came in From the Cold" (1965), as Moses Weiss in TV's "Holocaust" (1978) and ironically as a lawyer who tries to convince his clients to name names to HUAC in Irwin Winkler's Hollywood blacklist drama, "Guilty By Suspicion" (1991).

A veteran director for stage and TV ("The Defenders", "Columbo", "Hart to Hart"), Wanamaker's occasional directorial outings for film yielded mostly unexceptional results.