A prolific film and television composer, orchestra conductor, soundtrack orchestrator and arranger, Klatzkin worked in the music department of the Hal Roach Studios as a musician for eight years, afterwards working throughout Hollywood, notably for 20th Century-Fox. Klatzkin joined ASCAP in 1952, and his list of compositions there numbers over 600, nearly all of them themes for film and television. In the 1960s, Klatzkin was under contract to CBS television, and composed and arranged for many shows there, including 84 episodes of the popular western series Gunsmoke.

The opening and closing theme of the TV series Adventures of Superman is credited to Leon Klatzkin. Despite ASCAP and the Los Angeles Times listing his many compositions for television shows,^[2] some^[who?] suggest that Klatzkin was nothing more than a Mutel employee; A film cutter who helped editors select appropriate tracks for their pictures. There is a veritable industry dedicated to the attribution of the Superman theme to various other composers^{[citation needed]}. Klatzkin reached a settlement with John Williams over Williams' appropriation of the Superman theme - With proceeds going to a children's charity. The dispute with Williams appears to have inspired the noted disparagement.

• Inner Sanctum (1948)
• As You Were (1951)
• Captain Scarface (1953)
• Two-Gun Lady (1955)
• Go, Johnny, Go! (1959)

• Terrace, Vincent. Encyclopedia of Television Pilots, 1937-2012. McFarland, 2013.

• Classic 50's TV Themes
• Leon Klatzkin at IMDb