Arlen was born Hymen Arluck, the son of a synagogue cantor, in Buffalo, New York. He grew up in Buffalo attending public schools and private music study. By age 7 he was singing in his father’s synagogue chore and by age 15 he had become a professional pianist and entertainer in night clubs and lake steamers. In his late teens he organized The Snappy Trio, which later became The Southbound Shufflers, and the trio found its way to New York City. In Manhattan, Arlen found a home as a singer, pianist and arranger with dance bands and eventually with Arnold Johnson’s pit orchestra for the Broadway revue George White’s Scandals of 1928. Arlen appeared at the Palace Theatre in New York and did several tours with Loew’s vaudeville circuit.

Arlen continued to work on Broadway writing songs for musicals 9:15 Revue, Earl Carroll Vanities (1930 and 1932), Americana, George White’s Music Hall Varieties, and The Show is On. He also wrote entire scores for the Broadway shows You Said It, Cotton Club Parade, Life Begins at 8:40, Hooray For What, Bloomer Girl, St. Louis Woman, House of Flowers, Jamaica, Saratoga and Free and Easy. He was also active in Hollywood producing some of the greatest film musicals of the era including The Wizard of Oz, Let’s Fall In Love, Blues In the Night, Star Spangled Rhythm, Cabin In the Sky, Up in Arms, Kismet, My Blue Heaven, Gay Purr-ee, Down Among the Sheltering Palms and A Star if Born.

Arlen collaborated with many Tin Pan Alley, Broadway and Hollywood lyricists, including E.Y. "Yip" Harburg, Johnny Mercer, Ted Koehler, Leo Robin, Ira Gershwin, and Dorothy Fields.

Arlen died in New York City on April 23, 1986.