FitzSimons, Walter (a.1455–1511), archbishop of Dublin and deputy chief governor, was son of Robert FitzSimons and his wife Joan Cusack, and was a native of Dublin with a lifelong connection to St Patrick's cathedral, Dublin. He appears as precentor of the cathedral in 1476, served as the chapter's proxy in the parliament of the same year, and served as vicar general of the diocese before he was provided to the see (June 1484), becoming the first archbishop to be consecrated in St Patrick's. He joined in the general support for the pretender Lambert Simnel (qv), and may actually have crowned ‘Edward VI’ in Christ Church (May 1487). Although he was reconciled to Henry VII, his conduct in 1487 was the subject of an inquiry delegated to the archbishops of Tuam and Cashel by the pope (January 1488). He was appointed deputy lieutenant in May 1492 to replace Gerald FitzGerald (qv), 8th earl of Kildare, who was implicated in the Perkin Warbeck (qv) affair.
FitzSimons was to share his authority with Sir James Ormond (Butler) (qv), holding the official position of deputy and having responsibility for the Pale. He summoned a parliament in June 1493, and used his power while in office to attack the interests of Kildare's partisans, especially the treasurer, Roland FitzEustace (qv), Lord Portlester. However, without royal support FitzSimons proved incapable of keeping the peace in the Pale in the face of Kildare's hostility, and was removed from office (September 1493). His failure forced the king to adopt new measures and send a new administration, led by Sir Edward Poynings (qv), to Ireland. FitzSimons was summoned to England with Kildare and Sir James Ormond (September 1494) and was eventually reconciled to Kildare after Kildare regained the king's favour (1496). He served as chancellor from August 1496 to p.April 1505, possibly to the end of the reign in April 1509. He was Kildare's deputy (April–August 1503) while the earl was in England, and was sent as a messenger to the king with Kildare's report after the battle of Knockdoe in 1504. He died 14 May 1511 in Finglas and was buried in St Patrick's cathedral.