His mother was Richard Gresley's first wife, Caroline, youngest daughter of Andrew Grote, a London banker.
Having completed Westminster School as a king's scholar, Gresley matriculated at Oxford as a student of Christ Church on 21 May 1819.
In 1857 Gresley accepted the perpetual curacy of All Saints' Boyne Hill, near Maidenhead, Berkshire, where a church, a parsonage house and schools were being erected at the expense of three ladies living in the Oxford diocese.
In 1835 Gresley published Ecclesiastes Anglicanus: being a Treatise on the Art of Preaching as adapted to a Church of England Congregation, and in 1838 his Portrait of an English Churchman, which ran through many editions.
In 1839 he began with Edward Churton a series of religious and social tales under the general title of The Englishman's Library, 31 vols., London, 1840–39–46.
To The Juvenile Englishman's Library (21 vols., 1845–44–49), edited successively by his friends Francis Edward Paget and John Fuller Russell, he contributed Henri de Clermont, or the Royalists of La Vendée: a Tale of the French Revolution (vol.
Selection from the last two were published in 1879 as "The Scepticism of the Nineteenth Century", with a short account of the author and portrait of him by a former curate, S. C. Austen.