Just fourteen years old at the time of his father's death, Thomas was page of Richard II's child-queen, Isabella. The young Thomas was not allowed to assume the title of Duke of Norfolk, though it was not expressly revoked, and that of Earl Marshal, which he was allowed to retain, was dissociated from the office of Marshal of England, which was granted for life to the Earl of Westmorland. A small income was set aside from the revenue of the Gower estates for the support of Thomas and his younger brother John, and he was married towards the close of 1400 (aged 14) to the king's niece, Constance Holland, whose father John Holland, Duke of Exeter, had been beheaded in the preceding January.
Smarting under his exclusion from his father's honours, and perhaps urged on by discontented Yorkshire neighbours, the Percies and Scropes, Thomas joined the treasonable movements of 1405 against Henry IV, the old adversary of his father. On his own admission he was privy to the Duke of York's plot for carrying off the young Mortimers from Windsor in February of that year. But the king accepted his assurances that he had taken no active part in the conspiracy. Immediately afterwards he quarrelled with Richard Beauchamp, Earl of Warwick. the latter claimed, in a council on 1 March, precedence of Thomas as the holder of an earldom of earlier creation. The king decided in Warwick's favour, and Thomas retreated in dudgeon to the north, where the Earl of Northumberland was already preparing for revolt.
Thomas joined Archbishop Scrope of York in formulating and placarding over that city a list of grievances in English, in one form of which the king was denounced as a usurper. These articles hit most of the blots on Henry's administration, and some eight or nine thousand Yorkshiremen gathered round the two as they marched northwards from York to Thomas' country around Thirsk, where Sir John Fauconberg and other local knights were in arms. They were probably aiming at a junction with Northumberland and Lord Bardolf. but the king's second son John, afterwards Duke of Bedford, and Ralph Nevill, Earl of Westmorland, dispersed Fauconberg's forces at Topcliffe, a Percy lordship close to Thisk, and on 29 May intercepted the Earl Marshal and Scrope at Shipton Moor, five and a half miles north of York. It was against Thomas' judgement that Scrope consented to the fatal interview with Nevill, when the latter, assuming a spirit of friendly concession, induced the Archbishop to dismiss his followers. The leaders were then seized and hurried off to Pontefract, where the king arrived from Wales by 3 June. they were then brought to the Archbishop's house at Bishopthorpe, some two miles south of York.
The king's wrath was fanned by his half-brother, Thomas Beaufort, and by the young Earl of Arundel (Thomas' uncle) and he resolved that the prisoners should die where they had raised the standard of revolt. On the morning of Monday, 8 June 1405, the king called upon Chief-justice Gascoigne (whose mother was a Mowbray of Easby) to pass sentence on the Archbishop and his fellow-traitors. Gascoigne refused to sit in judgement on a prelate, and sentence of death was delivered in the name of the commissioners without form of a trial by another judge, Sir William Fulthorpe. The same day, the feast of St.William of York, and a holiday in the city, the condemned men were led out to execution before a great concourse of citizens in a cornfield under the walls of the city. Thomas showed some natural fear of death, but was encouraged by companion to keep a stout heart. He was beheaded before the Archbishop, and his body buried in the Grey Friars Church, but his head was fixed on a stake on Bootham Bar.
Thomas had no issue and was succeeded by his brother, John.