Cobb entered films in the 1930s, successfully playing middle-aged and even older characters while he was still a youth. His first credited role was in the 1937 Hopalong Cassidy oater "Rustlers' Valley", where he was billed using the stage name Lee Colt. In all subsequent films, he used Lee Cobb and later Lee J. Cobb. He was cast as the Kralahome in the 1946 non-musical film "Anna and the King of Siam". He also played the sympathetic doctor in "The Song of Bernadette" and appeared as Derek Flint's (James Coburn) supervisor in the James Bond spy spoofs "Our Man Flint" and "In Like Flint". He reprised his role of Willy Loman in the 1966 CBS television adaptation of the famous play "Death of a Salesman", which included Gene Wilder, James Farentino, Bernie Kopell, and George Segal. Cobb was nominated for an Emmy Award for the performance. Mildred Dunnock, who had co-starred in both the original stage version and the 1951 film version, again repeated her role as Linda, Willy's devoted wife.