He was born in 1262 at Lenton Priory in Nottinghamshire (to which his maternal ancestors the de Greasley family had been benefactors), the son and heir of Sir Nicholas de Cantilupe (d.1266) of Withcall (an ancient Cantilupe possession) in Lincolnshire, Greasley in Nottinghamshire and Ilkeston in Derbyshire, by his wife Eustachia FitzHugh, daughter and heiress of Ralph FitzHugh of Greasley (whose mother was Agnes de Greasley, heiress of Greasley and Ilkeston) and of Middle Claydon in Buckinghamshire.