Adam Sisman was born in London in 1954, the eldest child of David and Marjorie Sisman. The family was then living in Italy, where Adam spent his early years. Back in England, he attended St Paul's School and then the University of Sussex, where he read history. After graduating, he worked in book publishing for a dozen years before beginning to write. In 1979 he married Robyn Sisman, whom he had met as a colleague in his first job, and who also became a writer. She died in 2016. They had two daughters, one of whom has two young daughters of her own. Adam now lives in Bristol.

Adam is a frequent lecture, and has spoken at numerous events in Britain, Europe and America. In 2022 he gave the Carnegie Lecture at the University of St Andrews, where he is an Honorary Professor. He is also a former President of the Johnson Society of Lichfield, a Fellow of the Royal Society of Literature, and a member of the Society of Authors, the Biographers’ Club, Two Brydges, Soho House and the Literary Society.