In a royal order from Westminster in September 1247, Sir John Fitzgeoffrey was charged by the king with seizing the lands of Walter de Burgh's older brother Richard, who had died.

The traditional account that Walter de Burgh became earl of Ulster through marriage to a cousin is no longer generally accepted.

[6][2] In 1270, he and Walter de Ufford, the Justiciar of Ireland, were defeated by Aedh mac Felim Ua Conchobair at Áth an Chip.

He married Avelina, daughter of Sir John Fitzgeoffrey, Justiciar of Ireland, about 1257.

Other children were three sons, Theobald, William and Thomas, and a daughter, Egidia, who married Sir James Stewart (1260–1309), 5th High Steward of Scotland.