Watson was educated at St John's Grammar school and at the Hamilton Academy, subsequently attending the Glasgow University, graduating in Arts in 1954 and in Law in 1957.

He later served as Distinguished Research Professor and held the Ernest P. Rogers Chair at the University of Georgia School of Law.

Watson regularly served as a distinguished lecturer at leading universities in the United States and such countries as Italy, Holland, Germany, France, Poland, South Africa, Israel and Serbia.

In 2005, the University of Belgrade's Law School established the Alan Watson Foundation in honour of his worldwide scholarship.

Watson was honoured by his international colleagues in 2000–01 when two collections of essays were presented in his honour: an American volume, Lex et Romanitas: Essays for Alan Watson, and the European volume, Critical Studies in Ancient Law, Comparative Law and Legal History.