DeVito was born in Neptune Township, New Jersey, the son of Julia, a homemaker, and Daniel Michael DeVito, Sr., who owned several small businesses, including a dry cleaning store, a dairy outlet, a luncheonette, and a pool hall. DeVito grew up in a family of five, with his parents and two older sisters. DeVito is of Italian descent (his family is originally from San Fele, Basilicata) and was raised a Roman Catholic, growing up in Asbury Park. He boarded at Oratory Preparatory School, in Summit, New Jersey, and graduated in 1962. DeVito went to the boarding school at the age of 14, after he persuaded his father to send him there as it would keep him out of trouble. After leaving the boarding school he subsequently trained at the American Academy of Dramatic Arts, from which he graduated in 1966. In his early theater days, he performed with the Colonnades Theater Lab, Eugene O'Neill Theater Center, and, along with his wife Rhea Perlman, appeared in plays produced by the Westbeth Playwrights Feminist Collective.