Keate was educated at Eton College and later Christ Church, Oxford.
[4] He graduated in 1836 and was awarded his Masters degree in 1842 before being called to the bar at Lincoln's Inn in 1844.
He also played first-class cricket for the Gentlemen of Kent, a Fast Bowlers side, the Gentlemen of England, a Hampshire XI, and an England XI against Kent in 1840.
Keate later joined the colonial civil service upon, and was sent to the West Indies in 1857 as Governor of Trinidad, a position he held from 26 January 1857 to 1864.
In 1867, Keate was appointed the Lieutenant-governor of the Colony of Natal, a position he held from 1867 to 1872.