He also experienced success on Broadway with Angel in the Wings and Hazel Flagg. However, he is probably most celebrated as the lyricist for the film score to Alice in Wonderland. This included providing the words to the song - "I'm Late".
Throughout his career, Hilliard collaborated with many composers and lyricists including Burt Bacharach, Carl Sigman, Jule Styne, Mort Garson, Sammy Mysels, Dick Sanford, Milton DeLugg, Philip Springer, Lee Pockriss and Sammy Fain.
Married to Jacqueline Dalya, Hilliard was inducted into the Songwriters Hall of Fame in 1983.