 Leopold has often been associated with Chevy Chase, Harry Shearer, and Paul Shaffer due to his work with them on various projects.He also provided vocal performances with Jonathan Katz in animated productions for the Internet such as "Hey, We're Back" and "Explosion Bus".Leopold began writing material for "National Lampoon" magazine and went on to work on "The National Lampoon Radio Hour" when it was created in 1973.