He served for many years as Professor of Political Science at the London School of Economics, and was also known for his popular publications.

In the late 1970s and early 1980s he was Professor of Political Theory at the European University Institute in Florence (Italy).

[4] Cranston's major works include biographies of John Locke, for which he received the 1957 James Tait Black Memorial Prize, and Rousseau, Jean-Paul Sartre and others addressing the history of liberty.

Under the name Michael Stone, he also wrote a children's school story The Master of Magic, published by Peter Lunn in 1947.

Professor Kingsley Smellie pointed to a bottle and said to Cranston: "I hope you've ordered buckets of that stuff".