His broad interests were the history of medieval England, Ireland, Scotland and Wales.
He had a special concern with first-hand work on the primary sources of medieval history, including the practices of palaeography, diplomatic and the editorial process, as well as the historical and legal contexts of medieval documents.
[4][5] Sharpe studied at St Peter's School, York and then took his BA at Trinity College, Cambridge, studying Classics for Part I of the degree and then Anglo Saxon, Norse and Celtic for Part II, where he studied with, amongst others, Simon Keynes, Kathleen Hughes and Michael Lapidge.
[8][9] From 1981 to 1990, Sharpe was an assistant editor of the Dictionary of Medieval Latin from British Sources.
[10] As the University of Oxford's 2018–2019 Lyell Reader in Bibliography, Sharpe delivered that year's Lyell Lectures on the topic of "Libraries and Books in Medieval England: The Role of Libraries in a Changing Book Economy".