His grandfather, William de Tracy (died ), was an illegitimate son of King Henry I and the king granted him the feudal barony of Bradninch, Devon, which had escheated to the crown from William Capra, listed in the Domesday Book of 1086 as holding that barony.
William de Tracy appears in a charter of his older brother Ralph de Sudeley (died ) assigning the manor of Yanworth, near Cirencester, to Gloucester Abbey.