Born in Vienna, Austria, the son of opera tenor Leo Slezak and Elsa Wertheim, he studied medicine for a time and later worked as a bank teller. He was talked into taking his first role, in the 1922 Austrian film Sodom und Gomorrah, by his friend and the film’s director, Michael Curtiz. In his early movie career, before he gained a great deal of weight, Walter Slezak was cast as a thin leading man in silent films. He also acted on the stage for many years, debuting on Broadway in 1931. In Vienna in the 1930s, Slezak was close friends with Gustav Klimt Heiress Maria Altmann and her family – the wealthy, influential Bloch-Bauers – and he and Altmann continued their friendship when both emigrated to America in the early 1940s. His first American film was Once Upon a Honeymoon (1942), with Ginger Rogers and Cary Grant. He worked steadily and appeared in over 100 films including The Princess and the Pirate (1944), The Spanish Main (1945), Sinbad the Sailor (1947), Born to Kill (1947), Abbott and Costello in the Foreign Legion (1950), People Will Talk (1951), and Call Me Madam (1953). Slezak played the lead in Broadway musicals, including Fanny, for which he won the Tony Award for Best Actor in a Musical. Slezak acted in radio in such shows as Lux Radio Theater, Columbia Workshop, The Pepsodent Show, and The Charlie McCarthy Show. He made numerous television appearances, including in the programs This Is Show Business, Playhouse 90 and Studio One, and appeared as The Clock King in episodes 45 and 46 of TV series Batman (1966). In the 1970s, Slezak played the non-singing role of Frosch, the jailer, in the San Francisco Opera production of Johann Strauss’ operetta Die Fledermaus. Later popular film roles in Britain included the Cliff Richard vehicle Wonderful Live and Black Beauty. On April 21, 1983, 12 days before his 81st birthday, Walter Slezak died from a self-inflicted gunshot wound. He was reportedly despondent over his advanced physical illness. As was his father, he is buried in the Bavarian village Rottach-Egern.