He was educated at Thornleigh College, Bolton, and while at Manchester University was called up to the army. Hackney was posted to Maidstone Barracks for one year where he met his first wife and was later posted to India. After demobilisation he proceeded to New College, Oxford where he read Politics, Philosophy and Economics under the tutelage of Isaiah Berlin.
He was best known for his two novels Private's Progress and Private Life, which were both adapted into films, the former as Private's Progress (1956) and the latter as I'm All Right Jack (1959). Hackney also co-wrote the script of I'm All Right Jack, which was a satire of trade unions. He was also a frequent contributor to Punch.
At around this time the British film industry collapsed and Hackney’s career was never to hit such heights again. A further two children meant that he had to travel to write and he had spells in Canada, Italy (with the RAI TV series K 2 +1, directed by Luciano Emmer, starring the Kessler Sisters and Johnny Dorelli), and Hollywood as well as working for British television and continuing to contribute to Punch.
In recent years he worked with the composer Howard Blake on a musical version of I'm All Right Jack. His best-remembered films are Two-Way Stretch (1960), starring Peter Sellers, and You Must Be Joking (1965), directed by Michael Winner.
His success writing for the television series The Adventures of Robin Hood and the 1960 film Sword of Sherwood Forest enabled him to buy an Edwardian house in Bovingdon, Hertfordshire where he spent the rest of his life, first with his wife, Peggy until her she died in 1995 and then later with the Canadian film producer Daisy de Bellefeuille, whom he nursed through a long illness until her death in 2006.
Alan Hackney died in 2009, aged 85; he was survived by his six children.