Credited with pioneering the "Production Code" in Hollywood, a set of industry guidelines for self-censorship later replaced by the MPAA rating system.

Thalberg helped create Metro-Goldwyn-Mayer, being made head of production in 1925 and helping MGM become the most successful studio in Hollywood. He has been called by Hollywood's producers the world's "foremost figure in motion-picture history", and was personally mourned by President Franklin D. Roosevelt.