The Walwyns were an ancient marcher family, descended from one Philip Walwyn who held Walwyns castle, Pembrokeshire, and lands in the neighbourhood of Hay-on-Wye, Breconshire, in the reign of William Rufus. Thomas himself was the son of the John Walwyn who, having proved his age in 1362, then inherited the chief family manor of Stoke Edith. Nothing of significance is known about his early life, but by 1391 (as Thomas Walwyn junior) he was an esquire in the household of Bishop John Trefnant of Hereford. (In January of that year he was in attendance at the episcopal palace of Whitbourne when the lollard, Walter Brut, made some of his heretical statements.) It appears to have been Thomas of Stoke Edith who, as a King’s esquire, was specially granted robes of the royal livery in February 1394. But, although he crossed to Ireland in Richard II’s train later that year, he must have come home before the King, for it was undoubtedly he who was elected to the Parliament of 1395. Indeed, on 29 Jan., during the session, he was present in ‘quadam alta camera’ in the palace of Westminster when Bishop Trefnant lodged a complaint with Archbishop Courtenay against John Prophet, dean of Hereford and clerk of the privy seal, regarding the latter’s right to hold a certain prebend; and later that same day he was also present at Trefnant’s London hospice when the dispute underwent further developments. He evidently maintained his links with the bishop, for in March 1404 he was named as one of the executors of his will, along with his relation, William Walwyn. Subsequently, both he and William were among those appointed by Trefnant’s successor, Bishop Robert Mascall, to take action for the defence of the episcopal stronghold of Bishop’s Castle against the Welsh rebels. In December 1405, along with his father, John, his brother, Richard, and William Walwyn, Thomas obtained the reversion of moieties of the manors of Wellington and Fownhope, Herefordshire, after the death of Sir John Chandos and his wife.
To what extent, if any, this Thomas Walwyn was involved in county administration is unclear, for his career in this field is virtually impossible to disentangle from that of his older relation Thomas Walwyn II of Much Marcle, with whom he was sometimes associated. The latter had, indeed, as sheriff of Herefordshire, presided over his single election to Parliament. In March 1408, as Thomas junior, he was a surety when his namesake of Much Marcle obtained a royal lease of the custody of the alien priory of Wootton Wawen, Warwickshire. A month later, similarly described, he received a legacy of £40 (‘to his furtheryng’) in the will of William Beauchamp, Lord Abergavenny, whom the elder Thomas served as both feoffee and executor. Finally, in 1415, our Member took on the executorship of his kinsman’s will.