Newport’s background remains obscure, although it seems likely that he was a kinsman of aliasGech " rel="nofollow" href="NEWPORTTXXXX">Thomas Newport alias Gech† of High Ercall, Shropshire, who sat as a shire knight in the Parliament of November 1380, and served for a long period on the local bench. On being bound over to keep the peace in February 1401, Thomas’s son called upon him to act as one of his mainpernors, which suggests that some family connexion existed between them.
By the date of his first return to Parliament in 1407, Newport had established himself not only as a local figure of some consequence, but also as a soldier with a distinguished record in the field. He was one of the leading residents of Staffordshire to be summoned in July 1401 to attend a great council, and in the following November he began the first of three terms as sheriff, being chosen for the last time while the Commons of 1407, of which he was a Member, was still in session. Together with Sir Thomas Aston and other prominent Staffordshire landowners, he was chosen by John Burghill, bishop of Coventry and Lichfield, to act as a proxy in the Parliament of October 1404, which actually met at Coventry. During Henry IV’s campaigns against the Welsh Sir William served in the retinue of Henry, prince of Wales, whom he first indented to serve with a retinue of 29 esquires and 150 archers in March 1403, and subsequently attended with varying numbers of men over the next few years. The prince singled him out for particular praise in March 1405, after a hard-fought engagement in Glamorgan. He was present with his royal commander at the siege of Aberystwyth; and in September 1407 helped to officiate while terms of surrender were discussed. His loyalty was rewarded with the grant of the manor of Aber in Carnarvon, which was made to him for life by Prince Henry, and which increased his landed income by at least 40 marks a year, the value of yet another annuity, assigned to him in, or shortly before, 1408, by his patron as well. He also became constable of Beaumaris castle and sat as such during at least one of the three Parliaments to which he was elected.
Over the years, Newport became involved both directly and indirectly in the affairs of his neighbours. In 1401, for example, he offered sureties in Chancery on behalf of Sir John Bagot (his parliamentary colleague in 1407 and 1411), who was then at odds with members of the Gresley family.
Newport died in the summer of 1416, being succeeded by his son, William, a somewhat less eminent but equally truculent member of the Staffordshire gentry. His widow, Margaret, survived him, and he also left at least one daughter, who appears to have married Ralph, the son of Sir Ralph Bracebridge of Kingsbury, Warwickshire, in about 1411.
