williams was a reader in english law then professor of public law and quain professor of jurisprudence at the university of london from 1945 to 1955. he then moved to the university of cambridge and was a fellow of jesus college, cambridge, and a reader in law from 1957 to 1965, then professor of english law from 1966 to 1968. he then became the rouse ball professor of english law from 1968 to 1978. he was elected a fellow of the british academy in 1957.