In his youth Thomas was a notable sailor, receiving the freedom of the City of London in 1454 for his work in eliminating pirates from the English Channel and the North Sea.
In this he was closely associated with his father's relatives: Lord Fauconberg's elder brother, Richard Neville, Earl of Salisbury was a commissioner for the keeping of the seas in 1453–1455, and in 1455 Salisbury's eldest son Richard Neville, Earl of Warwick, was entrusted with sole responsibility for the keeping of the seas, a post he effectively retained for the rest of his life.
The Nevilles were the most important supporters of Richard of York, and instrumental in helping his son gain the throne as Edward IV in 1461, assistance for which Lord Fauconberg was rewarded with the title of Earl of Kent.
When he died in 1463 without a legitimate male heir, the barony of Fauconberg fell into abeyance between his three daughters: Joan, Alice and Elizabeth.
[2] In 1471 Thomas was back at sea for the Lancastrians, serving under Warwick in defence of the government of Henry VI, who had regained the throne with the Nevilles' help in 1470.
However, before these reinforcements could intervene, Edward occupied London, took Henry VI prisoner, and defeated and killed Warwick in the Battle of Barnet on 14 April.
[3] With his cousin dead, Thomas landed at Sandwich, sending his ships to sail around Kent and up the Thames Estuary.
He himself advanced over land towards London, gathering troops as he went, and received notable support from Canterbury and its mayor Nicholas Faunt.