Peter Emsley was educated at Westminster (1788-1791) and at Christ Church, Oxford. Graduating in 1794, he hoped for a fellowship at Merton, but failing in this he left Oxford. Proceeding to the degree of M.A. in 1797 and having been ordained, in 1798 he was presented with the living of Little Horkesley, Essex. In 1802, however, he gave up residence, having inherited a large sum from his uncle (Peter Elmsley, a wealthy and well-known bookseller in the Strand). This new-found independence enabled him to devote the rest of his life to scholarship, in particular textual criticism of Euripides and Sophocles. In addition, in 1802 he met Sydney Smith in Edinburgh, who was just founding the Edinburgh Review, and Elmsley became a frequent contributor; subsequently he transferred his allegiance to the Quarterly Review.
After spending some years in London, Elmsley moved in 1807 to St. Mary Cray, Kent, in order to live with his mother. While there he met Grote, the future historian of Greece; they both paid court to the same young woman, but she preferred, and married, Grote. In 1816 Elmsley left St. Mary Cray and returned to Oxford, where he lived the rest of his life, with the exception of the winter of 1818, which he spent in Florence collating the manuscripts of the Scholia to Sophocles in the Laurentian Library, and a period from the end of 1819 to the middle of 1820, when he joined the abortive expedition to Naples with Sir Humphrey Davy to decipher the Herculaneum papyri. In 1823 he took the degree of D.D., and became simultaneously Camden Professor of Ancient History and Principal of St. Alban’s Hall (which ironically was in due course absorbed by Merton, which had rejected him as a fellow). He remained in both posts for the last two years of his life, dying suddenly of heart disease in March, 1825.
Elmsley’s name has survived as that of a philologer and editor (he has been described as ‘the best Greek scholar as yet produced by Oxford’, and many compared him to Richard Porson), but his knowledge of ecclesiastical and constitutional history was thought unrivalled; and his knowledge of ancient history was deemed worthy of a professorship. He was a great traveller, and wrote long and detailed letters recounting his journeys. Rich, obese, gossipy and genial, he corresponded very widely, particularly with the scholars James Monk, Charles Blomfield and Thomas Gaisford, and with his former schoolfellows George Bedford and Charles Watkin Williams-Wynn (who erected a monument to him in Christ Church Cathedral).