Although he earned a scholarship to Oxford University to read history he never took it up, choosing to work on the railway instead. Smith’s initial interest in law was developed whilst he was serving in the British Royal Artillery and subsequently he helped administer courts martial. After leaving military service he read law at Cambridge University and became a barrister in 1950.
For many years he was a professor of Law at Nottingham University and was influential in making the university one of the premier institutions for legal education in England. He also spent a year at Harvard University.
During the 1960s Smith was a member of the Criminal Law Revision Committee. The resulting recommendations played an important part in the development of the Theft Acts of 1968 & 1978.
Smith was a fellow of the British Academy. He was made QC in 1973 and knighted in 1993.