By the early 14th century, if not before, members of the Barber family were playing an important part in the government of the borough of Stafford, and Thomas chose to follow the example of his ancestor, Nicholas Barber, who sat in the Parliament of 1312 and was later made bailiff of the town. It is unlikely, on chronological grounds alone, that he was the Thomas Barber who had by 1398 acquired property in Burton, Staffordshire, jointly with his wife and adult son, Henry, although the two namesakes were almost certainly related. We know that the MP owned a close in Burton, which was the subject of a lawsuit brought by him just before his death, and which may have formed part of his inheritance. Yet most of Barber’s holdings lay in and around Stafford: he rented a tenement in the town and farmland in the surrounding countryside from the earls of Stafford, and is generally described as a local yeoman during the earlier part of his life.
Not much evidence survives about Barber’s career until after his last return to Parliament. Towards the end of Henry IV’s reign he wore the livery of the notorious trouble-maker, Hugh Erdeswyk, who was indicted, among a whole litany of offences, in 1413 for breaking the statute on illegal retaining. In common with Erdeswyk and the majority of his supporters, Barber joined the affinity of Humphrey, earl of Stafford, soon after the latter’s coming of age in 1423, and it was through the earl’s patronage that he achieved a prominent place in county society. His experience as a former MP and bailiff of Stafford clearly worked to his advantage, for by 1425 he had been made receiver-general of the earl’s English and Welsh estates, a demanding post which involved almost continuous travel and required considerable financial expertise. Together with his colleagues, Robert Whitgreve and John Harper, he was party to a number of Earl Humphrey’s property transactions as both a feoffee-to-uses and an attorney. He also witnessed several deeds for the earl and his tenants. Although he earned a fee of ten marks a year and probably made far more through the perquisites of office, Barber found that his post was not without its drawbacks. In 1429, for example, he and Earl Humphrey were sued for assault and robbery by certain tenants of the manor of Wexcombe in Wiltshire. His claim to have been within the law in confiscating the goods of his employer’s villeins carried little weight with the local jury, and he and the earl were obliged, despite their appeal, to pay fairly heavy damages to the plaintiffs.
At about Michaelmas 1434 Barber exchanged his receiver-generalship for the less exacting post of receiver of Earl Humphrey’s Staffordshire estates alone, perhaps because of age or infirmity. He was by then a leading figure in the county: he had witnessed the parliamentary returns of May 1413 and 1431, and in May 1434 he was included among the notables of Staffordshire who were to take oaths not to maintain persons breaking the peace.