From 1966 to 1970 he taught at the University of California, Berkeley. Since 1970 he has taught at the University of Toronto.
Cook is best known for his formulation of the notion of NP-completeness and his proof that satisfiability is NP-complete. He has published about one hundred papers in theoretical computer science, including fundamental results in parallel complexity.
Cook won the ACM Turing award (computer science's highest award) in 1982. He is a fellow of the Royal Society of Canada (1984) and a member of the US National Academy of Science (1985). In his spare time, Cook enjoyes sailing and playing the violin.