Styne attended Chicago Musical College, but before then he had already attracted attention of another teenager, Mike Todd, later a successful film producer, who commissioned him to write a song for a musical act which he was creating. It would be the first of over 1,500 published songs Styne would compose in his career. Styne established his own dance band, which brought him to the notice of Hollywood, where he was championed by Frank Sinatra and where he began a collaboration with lyricist Sammy Cahn, with whom he wrote many songs for the movies, including "It's Been a Long, Long Time, "Five Minutes More", and the Oscar-winning "Three Coins in the Fountain."
In 1947 Styne wrote his first score for a Broadway musical, "High Button Shoes," with Cahn, and over the next several decades wrote the scores for many Broadway shows, most notably "Gentlemen Prefer Blondes", "Peter Pan", "Bells Are Ringing", "Gypsy", "Do Re Mi", "Funny Girl", "Sugar", and the Tony-winning "Hallelujah Baby!" His collaborators included Betty Comden and Adolph Green, Stephen Sondheim, and Bob Merrill, and among the songs in those shows composed by Styne are "I Still Get Jealous," "Diamonds Are a Girl's Best Friend," "Just In Time," "The Party's Over," "Make Someone Happy," "Everything's Coming Up Roses," "Let Me Entertain You," and "People."