Although thin and healthy when he began his film career in the 1920s, by the 1930s, he had gained much weight. He committed suicide by shooting himself in the backyard of his home in Flower Hill, New York, apparently in despair over several illnesses he was dealing with by then.
Brother of actress Margarete Slezak.
Father-in-law of actor Brian Davies.
Grandfather of actress Amanda Davies and actor Tobias Slezak.
He was married to Johanna Van Ryn, with whom he had three children, including daughter Erika Slezak, actress, born August 5, 1946. Daughter Ingrid was the first, followed by Erika and then son Leo, named after his father.
He was the son of Leo Slezak, operatic tenor (Aug. 18, 1873 - June 1, 1946), later a comedian in Austrian films. Leo Slezak was a famous Lohengrin, and is credited with this story: during one production of the opera "Lohengrin," when the mechanical swan that was to carry the hero across the lake malfunctioned and "floated" off too soon, he was heard to say, "What time is the next swan?". This quote became the title of Walter Slezak's autobiography.
Won Broadway's 1955 Tony Award as Best Actor (Musical) for "Fanny."