Fortescue was the eldest son of Sir John Fortescue, Captain of Meaux, and brother to Sir John Fortescue, Lord Chief Justice of England and Wales.
Fortescue was the eldest son of Sir John Fortescue, appointed in 1422 Captain of the captured Castle of Meaux, 25 miles NE of Paris. His younger brother was Sir John Fortescue, Lord Chief Justice of England and Wales.