Mandel started out as a trumpet player in the early forties, but quickly made a name of himself as a first-call New York City arranger, the one in charge of the whole sonic picture for artists such as Count Basie. He then became a legendary Hollywood figure, writing and arranging soundtracks to many movies, including The Shadow Of Your Smile and the Theme From M.A.S.H. which has been covered among others by the Manic Street Preachers and Marilyn Manson.