FitzGerald, Thomas fitz Thomas (c.1458–1487), chancellor, was second son of Thomas fitz Maurice FitzGerald (qv), 7th earl of Kildare, and his wife Joan, daughter of James fitz Gerald FitzGerald (qv), 7th earl of Desmond. He had a short career in the 1480s, but rarely appears as an independent actor in the sphere of Anglo-Irish politics. His brother Gerald fitz Thomas (qv), 8th earl of Kildare, appears to have used him to cement the Kildare hegemony over Anglo-Irish politics by marrying him to a daughter of Robert Preston (qv), Viscount Gormanston, one of the most prominent leaders of the Anglo-Irish of the Pale. He was also knighted and granted lands in Lackagh, for which he received a parliamentary subsidy (1484) to aid in the construction of a castle. He was appointed to the office of chancellor of Ireland by his brother (1483), probably early in the reign of Richard III, and was present at the parliament that formalised the supposed statute of Henry fitzEmpress. Thomas also joined with his brother to found a chantry in the church of St Nicholas, Dundalk.
In his most independent move, he was one of the first members of the Anglo–Irish community to accept the claims of the pretender Lambert Simnel (qv); he provided Simnel with a base from which to act in Dublin and was probably instrumental in convincing Kildare to accept Simnel's claims. Thomas attended the coronation of ‘Edward VI’ (24 May 1487) and resigned his office of chancellor in early June to lead the contingent of Irish troops that joined the pretender and his force of German mercenaries in their invasion of England. Simnel's force left Dublin on 4 June 1487 and landed in England, where at Stoke (16 June 1487) they met the royal forces, who defeated them, captured Simnel, inflicted heavy losses on the Irish, and killed Thomas. His death did not immediately make his brother forsake his allegiance to ‘Edward VI’, but within a few months Kildare was forced to admit the futility of his position and seek a reconciliation with Henry VII.