He worked at SRI International for over 30 years, and was Principal Scientist at the Artificial Intelligence Center.
Stickel's research included Theory Resolution, Associative-Commutative (AC) Unification, and the development of the Prolog Technology Theorem Prover (PTTP) and SNARK, SRI's New Automated Reasoning Kit.
He was elected fellow of the American Association for Artificial Intelligence in 1992 and received the Herbrand Award for his contributions to automated deduction in 2002.