Born in Wilmington, Delaware, Longobardi received a B.A. from Washington College in 1952 and an LL.B. from Temple University School of Law in 1957. He was in private practice in Delaware from 1957 to 1959. He was a Deputy state attorney general of Delaware from 1959 to 1961. He was in private practice in Wilmington, Delaware from 1964 to 1974. He was a member of the Delaware Tax Appeal Board from 1973 to 1974. He was a judge on the Delaware Superior Court from 1974 to 1982. He was a Vice chancellor, Delaware Court of Chancery from 1982 to 1984.