He was the son and heir of Humphrey I and Maud, a daughter of Edward of Salisbury, an Anglo-Saxon landholder in Wiltshire. His father died around 1123 and he inherited an honour centred on Trowbridge, although he still owed feudal relief for this as late as 1130.
By 1130 the younger Humphrey also owed four hundred marks to the Crown for the Stewardship, which he had purchased. He appears in royal charters of Henry I towards 1135, and in 1136 he signed the charter of liberties issued by Stephen at his Oxford court. He repelled a royal army besieging his castle at Trowbridge, and in 1144 Matilda confirmed his possessions, granted him some lands, and recognised his "stewardship in England and Normandy".
In 1158 he appears to have fallen from favour, for he was deprived of royal demesne lands he had been holding in Wiltshire.
He does not appear in any royal act until January 1164, when he was present for the promulgation of the Constitutions of Clarendon. He left a widow in Margaret of Hereford, daughter of Earl Miles of Hereford and Sibyl de Neufmarché.
