Wilson was born in Stone in Staffordshire to a father who became the managing director of Wedgwood, the pottery company. He was first educated at Hillstone School (subsequently incorporated into Malvern College) in Great Malvern, Worcestershire, and then at Rugby School from the age of 13, where he read Mao and Marx in his spare time. While at Rugby, he wrote an article for the school magazine arguing that public schools should be abolished. The national press became interested in the story, with the Daily Express headlining its account “Red rebel in Tom Brown’s school”. “Reporters arrived at the school gates, wanting to interview me, but my housemaster, wisely, would not let me talk to them”, Wilson told Hunter Davies in 1993. After New College, Oxford, he taught English at Merchant Taylors’ School, Northwood, for two years and then spent seven years as a lecturer in medieval literature at St Hugh’s College and New College, Oxford. He married the Shakespearean scholar Katherine Duncan-Jones in 1971. They had two daughters, Emily Wilson (born 1971) and Beatrice “Bee” Wilson (born 1974), and divorced in 1990. He is now married to the art historian Ruth Guilding.

In 2001 Wilson published Dante in Love, a study of the Italian poet Dante Alighieri as an artist and philosopher, also depicting an in-depth portrait of medieval Florence to help readers understand the literary and cultural background which engendered the Tuscan’s masterpiece, The Divine Comedy.

In August 2006, Wilson’s biography of John Betjeman was published. It was later discovered that another biographer, Bevis Hillier, had sent him a forged letter which was included in the book.