Fitzgerald, Maurice fitz Thomas (c.1460–1520), 10th earl of Desmond, was second son of Thomas fitz James FitzGerald (qv), 8th earl of Desmond, and Alice Barry, and succeeded to the earldom after the assassination of his brother, James fitz Thomas FitzGerald (qv), 9th earl of Desmond, at the instigation of another brother, John (December 1487). He had been in conflict with James in September 1487 but was recognised by the king and given livery of his brother's lands (April 1488) and was appointed constable of Limerick castle. He was one of fifteen Irish peers summoned to court by Henry VII (1489), but did not obey the summons. In 1490 his quarrel with the Burkes was cited as the reason that Gerald FitzGerald (qv), 8th earl of Kildare, also failed to go to England; and in July 1491 Desmond was one of the signatories of a letter sent to the king supporting Kildare in Ireland and protesting allegiance to the king. He continued his brother's policy of entrenching Desmond power in Munster, where he faced an alliance of the Geraldines of the Decies and the MacCarthys of Muskerry; but he was also more active outside the traditional range of Desmond influence, raiding as far as Ely O'Carroll in 1489.
Desmond openly supported the pretender Perkin Warbeck (qv) as early as 1493, and was deprived of the constableship of Limerick castle in favour of Sir James Ormond (Butler) (qv) in June 1495. He led a force in support of Warbeck and besieged Waterford (23 July–3 August 1495) before retreating westwards to his home country; he made a modest pledge of good behaviour (March 1496), giving his son to the city of Cork as a pledge of good behaviour, and received an official pardon (August 1496). After this foray into national politics, he retreated into Munster, although he did maintain good relations with Kildare, and in 1510 joined Kildare in an attempt to destroy the bridge built by the O'Briens over the Shannon. A report (1515) by Sir William Darcy (qv) singled him out for condemnation for Gaelic practices. He married first Ellen Roche, daughter of Lord Roche of Fermoy, and secondly Honor, daughter of John FitzGibbon, the White Knight of Kerry. He seems to have turned much of the administration of his earldom over to his son James (qv) in the decade before his death in 1520. He was buried in Tralee, and James succeeded to the earldom.