Judd Asher Nelson (born November 28, 1959) is an American actor, screenwriter, and producer. He is known for his roles as John Bender in The Breakfast Club, Alec Newbary in St. Elmo's Fire, Nick Peretti in New Jack City, Billy Beretti in Empire, Jack Richmond in Suddenly Susan, and Hot Rod and Rodimus Prime in The Transformers: The Movie and Transformers: Animated.
Nelson was born in Portland, Maine. His mother, Merle (née Royte), was a court mediator and former member of the Maine state legislature. His father, Leonard Nelson, was a corporate lawyer. His family is Jewish, and his father was the first Jewish president of the Portland Symphony Orchestra. He has two sisters, Eve and Julie. He went to school at St. Paul's School in Concord, New Hampshire, and Waynflete School in Portland, Maine, and studied at Haverford College in Pennsylvania, leaving during his sophomore year. He subsequently moved to Manhattan to study acting with Stella Adler.