[1] He was born at Wells, Somerset, the son of Prebendary William Keate, rector of Laverton, Somerset, and brother of Robert Keate FRCS (1777–1857), Serjeant-Surgeon to King William IV and Queen Victoria.
He was educated at Eton, and was admitted to King's College, Cambridge in 1792, winning the Browne Medal in 1793, 1794 and 1795, and the Craven scholarship in 1794, graduating B.A.
[2] Taking holy orders, he became, about 1797, an assistant master at Eton College.
[4] Although his predecessor had been somewhat relaxed, and the teacher-pupil ratio was extremely low, the discipline of the school was not improved by the harsh measures that he took as headmaster, including large-scale floggings with the birch, resulting in mass rebellions by the boys.
Keate was made a canon of the eighth stall of Windsor in 1820.