Dropping out of school at 15 to join a juvenile vaudeville act, Lahr worked his way up to top banana on the Columbia Burlesque Circuit, and in 1927 moved to Broadway plays as a comic actor, performing classic routines such as Woodman, Spare That Tree!
Aside from Oz, however, his movie career never caught on, possibly because his gestures and reactions were too broad for that intimate medium. His later life was troubled, although he made the transition to straight theater, particularly in a much-praised version of Waiting for Godot.
Lahr died in 1967 in the middle of filming The Night They Raided Minksy's, forcing producers to use a double in several scenes. Fittingly, this last role was as a burlesque comic.