An easy listening arranger and composer, Winterhalter was born in Wilkes-Barre, Pennsylvania. He graduated from Mount St. Mary's near Emmitsburg, Maryland in 1931, where he played saxophone for the orchestra and sang in two of the choirs. He later studied violin and reed instruments at the New England Conservatory of Music. After graduating, he taught school for several years before turning professional during the mid-1930s, serving as a sideman and arranger for Count Basie, Tommy Dorsey, Raymond Scott, Claude Thornhill and others.
Winterhalter also arranged and conducted sessions for singers including Dinah Shore and Billy Eckstine, and in 1948 he was named musical director at MGM Records. After a two-year stint with the record label, he moved to Columbia Records, where he scored a pair of hits with his recordings of "Jealous Heart" and "Blue Christmas".
In 1950, Winterhalter signed on with RCA Victor, where he arranged sessions for many of their popular artists including Perry Como, Harry Belafonte, Eddie Fisher and the Ames Brothers; he also recorded several instrumental albums, among them 1952's Great Music Themes of Television, one of the first collections of TV theme songs ever recorded. Winterhalter also notched a series of chart hits, including "Mr. Touchdown, U.S.A.", "A Kiss to Build a Dream On", "Blue Tango", "Vanessa", "The Little Shoemaker", and "Song of The Barefoot Contessa". With pianist Eddie Heywood, he had a small hit with "Land Of Dreams" (1954) and reached the number two spot with 1956's "Canadian Sunset."
He remained with RCA Victor until 1963, at which time he moved to Kapp; that same year, he also penned the main title theme for the film, Diamond Head. At Kapp he recorded a handful of albums including The Best of '64 and its follow-up, The Big Hits of 1965, before leaving the label to work on Broadway. He later worked in television as well, and continued recording the occasional LP for various budget labels. His last US chart single was "Theme From 'Popi'", released on Musicor in 1969. It reached #35 in the Billboard Easy Listening Top 40.