Young was born Gerald Tommaso DeLouise in Queens, New York, the son of Josephine and Michael. He was trained by Lee Strasberg at the Actor's Studio. Young is widowed and has one daughter, Anne Morea.
Young made his name playing rough-edged working class Italian-American characters, the best-known example being his signature role as Sylvester Stallone's brother-in-law Paulie in Rocky (1976), for which he received an Oscar nomination for Best Supporting Actor. He is one of three actors (the other two being Stallone and Tony Burton) who have appeared in every Rocky film (although, additionally Talia Shire appears in Rocky I-V, and makes a flashback appearance in Rocky Balboa).
He has played similar roles in Chinatown (1974), Convoy (1978), [[Back to School, The Pope of Greenwich Village, Once Upon a Time in America (1984), Last Exit to Brooklyn, Downtown: A Street Tale, and even a brutal and darker role in Amityville II: The Possession. Young has also appeared in many television programs, including The Rockford Files, Baretta, Law & Order, Walker, Texas Ranger, M*A*S*H, guest-starred in a Miami Vice episode, and made an appearance on A&E's The Sopranos ("Another Toothpick") as Bobby Baccalieri's father, who is dying of cancer and comes out of retirement to execute a hit on his godson.
Young is also a talented visual artist, a painter whose art has been displayed in galleries throughout the world. He is also a published author whose works include two filmed screenplays and 400-page historically based novel called Endings.
He has also written two stage plays: SOS and A Letter to Alicia and the New York City Government From a Man With a Bullet in His Head.