He was the eldest son of Stephen, Count of Aumale, and his spouse, Hawise, daughter of Ralph de Mortimer of Wigmore.
William witnessed two charters of King Stephen in 1136, in which he is recorded as Willelmus de Albamarla, but is not placed among the earls.
[1] His Scarborough Castle was forfeited to King Henry II as a result of unauthorised construction during the Anarchy.
Hawise married three times, firstly, on 14 January 1180, William de Mandeville, 3rd Earl of Essex.
She married secondly after 3 July 1190, the crusader William de Forz (died 1195), by whom she had her heir and successor.