FitzGeoffrey, John (c.1206–1258), justiciar of Ireland, was the son of Geoffrey fitz Peter, 4th earl of Essex, justiciar of England, by his second marriage, to Aveline, daughter of Roger de Clare, 3rd earl of Hereford, and widow of William de Munchesney. He seems to have come of age in 1227, when he paid a fine to have seisin of some of his father's lands; however, the bulk of fitz Peter's estates passed to the descendants of his first marriage. FitzGeoffrey began his long career in royal service in 1234, when he became sheriff of Yorkshire; thereafter a large number of important administrative posts came his way, including the seneschalship of Gascony (1243). After Maurice FitzGerald (qv) was removed from the justiciarship of Ireland, the king informally appointed John in September 1245 and gave formal notification on 4 November the same year. FitzGeoffrey's departure for Ireland was delayed until early August 1246. His connections with Ireland predated his appointment as justiciar: in 1234 his marriage to Isabel, daughter of Hugh Bigod, earl of Norfolk, and widow of Gilbert de Lacy (d. 1230), the son and heir of Walter de Lacy (qv) (d. 1241), lord of Meath, brought with it a landed interest in the country.
FitzGeoffrey's tenure as justiciar of Ireland was a comparatively long one, but despite a number of lengthy absences in England (1247, 1250–51, and from June 1253, except for a brief visit in 1254) he was an active and successful administrator, imposing degrees of royal authority on areas that were traditionally outside the colony's control. Apparently a condition of his appointment was a generous increase in the salary usually paid to the justiciar, from 500 marks, which his predecessor had received, to £500 per annum. One of his main tasks was to ensure that Ireland was of value to Henry III in terms of revenue, foodstuffs, and patronage. He established a modus vivendi with Maurice FitzGerald, who had fallen from favour, and aided his rehabilitation in royal circles. In 1248 he was in Ulster supporting FitzGerald's invasion of Tír Conaill, and he built a bridge across the Bann at Coleraine and erected a castle at Kilowen. Because of his success, the Cenél nEógain sued for peace and handed over hostages. In 1249 he concentrated his activities in Connacht against the recalcitrant Áed O'Connor (qv) (d. 1274) and set up Áed's cousin Toirrdelbach as a rival king to Áed's father, Fedlimid O'Connor (qv) (d. 1265). In 1252 he was again in Ulster where he rebuilt Moycova in Down and secured the submission, though short-lived, of Brian O'Neill (qv), king of Tír Eóghain.
FitzGeoffrey showed himself willing to invest personally in Ireland when, in 1251, he bought from the king the wardship of the Butler minority at a price of 3,000 marks. He formed important alliances with some of the colony's leading families: one of his daughters married Walter de Burgh (qv), later earl of Ulster, another married Theobald Butler (qv) (d. 1285). He was probably instrumental in showing the king how Ireland could be exploited as a new source of patronage to reward the curiales who swarmed around Henry's court. He was a beneficiary of this policy when in August 1253 he was granted the cantred of the Isles in Thomond, which was given almost full liberty status. In September 1254 as a reward for his ‘immense and laudable service’ he was to hold it free of rent and knight service. He may earlier have been pivotal in negotiating an agreement between the king and Conchobhar O'Brien (qv) concerning Thomond. The latter years of his justiciarship were spent in partnership with his nephew Richard de la Rochelle (qv), who was appointed to look after the interests of the Lord Edward after he had been granted the lordship of Ireland on 14 February 1254. FitzGeoffrey's experience and ability were urgently required for Edward's forthcoming expedition to Gascony, and FitzGeoffrey was summoned back to England in June 1253, though he formally remained as justiciar until the appointment of Alan de la Zouche in 1256, probably in June.
In the political upheavals of 1258 FitzGeoffrey became one of the king's chief opponents. With Simon de Montfort he was the author of the confederation of magnates in August 1258. He was one of the twelve barons appointed to reform the realm and one of the council of fifteen nominated in the provisions of Oxford. His disillusionment, according to some chroniclers, stemmed from his removal as justiciar and resentment generated by the activities of the king's Poitevin half-brothers. Certainly the former has a ring of truth. His heavy investment in Ireland never really had an opportunity to bear fruit; though he was granted lands in Thomond, these were never colonised and always remained relatively unprofitable. He died suddenly on 23 November 1258 and, despite his hostility to the king, Henry III ordered a mass to be celebrated for his soul and donated a cloth of gold to shroud his coffin. He had three sons; the eldest died while he was still living and was succeeded in turn by John and then Richard.