He collaborated with numerous composers, including Henry Mancini, John Williams, and Anita Kerr. His symphonies, concertos, and other orchestral works have been performed by orchestras around the globe. His work as a composer in the film industry garnered him two Academy Award nominations for "The Prime of Miss Jean Brodie" (1969) and "A Boy Named Charlie Brown" (1969), and his other film scores have included "Joanna" (1968), "Me, Natalie" (1969), "Scandalous John" (1971), "The Borrowers" (1973) and "Emily" (1976). McKuen's contribution to "A Boy Named Charlie Brown", the first feature-length animation based on Charles M. Schulz's comic strip, "Peanuts", also included singing the title song. McKuen also earned a mention in the "Peanuts" strip dated October 3, 1969, in which Sally Brown expresses her frustration that she was sent to the principal's office for an outburst in art class, opining that Pablo Picasso and Rod McKuen surely must have had trouble drawing cows' legs when they were young.