Philip confirmed his father's gifts to the abbey of St. Florent in 1096. He was the first Braose Lord of Builth and Radnor, their initial holding in the Welsh Marches. Philip returned from the 1st Crusade in 1103. He built the Norman church of St Nicolas at Old Shoreham and founded the port of New Shoreham. His lands were confiscated by Henry I in 1110, due to his traitorous support of William, son of Robert Curthose but they were returned in 1112.
Philip de Braose possibly went on 2nd Crusade and died in Palestine. Philip confirmed the gifts of his nephew, Philip de Harcourt, to the newly established Knights Templar. This Philip, Bishop of Bayeux, bestowed the manor and church of Shipley on the Templars between 1125 and 1130 and in 1154 added St. Mary's, Sompting. Philip de Harcourt's brother was Richard de Rennesville, a Templar.

There are charters where Robert de Harcourt's sons, Philip and Richard, refer to Philip de Braose as "patruus" - paternal uncle. This lends weight to the theory that Robert de Harcourt and Philip de Braose were both sons of Eve de Boissey. In another record dated 1103 (Pipe Roll Soc. Vol 71 no 544) it is stated that Philip de Braose was represented by "his brother Robert, the son of Anketill".