[4] Wilson was born in Bexhill, Sussex, England, to an English father, William Johnstone-Wilson, and South African mother, Maude (née Caney), of a wealthy merchant family of Durban.

[5][6][7] Wilson's grandfather had served in a prestigious Scottish army regiment, and owned an estate in Dumfriesshire, where William Johnstone-Wilson (despite being born at Haymarket) was raised, and where he subsequently lived.

[6][7] Wilson was educated at Westminster School and Merton College, Oxford,[8] and in 1937 became a librarian in the British Museum's Department of Printed Books, working on the new General Catalogue.

He used to mince into the room wearing, in those days, outrageous clothes in all colours; he chain-smoked; his nails were bitten down to the quick and he had a rather hysterical laugh.Wilson returned to the Museum after the end of the war, and it was there that he met Tony Garrett (born 1929), who was to be his companion for the rest of his life.

[citation needed] Wilson's first publication was a collection of short stories, The Wrong Set (1949), followed quickly by the daring novel Hemlock and After, which was a great success, prompting invitations to lecture in Europe.

He was Professor of English Literature at the University of East Anglia from 1966 to 1978,[16] and jointly helped to establish their creative writing course at master's level in 1970,[17] which was then a groundbreaking initiative in the United Kingdom.