Saer de Quincy's immediate background was in the Scottish kingdom: his father, Robert de Quincy, was a knight in the service of King William the Lion, and his mother, Orabilis de Mar, was the heiress of the lordship of Leuchars in Fife (see below).
His own rise to prominence in England came through his marriage to Margaret, the younger sister of Robert de Beaumont, Earl of Leicester: but it is probably no coincidence that her other brother was the de Quincy's powerful Fife neighbour, Roger de Beaumont, Bishop of St Andrews.