Leupp is a native of City Island, New York. He is a 1983 graduate of Cardinal Spellman High School and studied theatre at Adelphi University. Calling himself "a gay guy who was never going to be passing for straight", he said that he had just started college when homophobic slurs were directed at him. "Here we go again, I thought; I was so used to it, in high school. But by the end of those four years, I had become very popular, by just being myself, and being relatable."