Admitted a freeman of Ipswich in September 1446, Wynter had a brother, William, also a burgess of the town.
Thanks to his prominence in commerce and ensuing local status, Wynter enjoyed a full role in borough affairs, in which he had begun to play a part before entering the Commons since he was elected to his only known Parliament during his second term as chamberlain of Ipswich. The formal indenture attesting his election to the Parliament of 1453 bears the date of 27 Feb., although the borough had already chosen its MPs four days earlier. The prosperous Wynter undertook to meet his own costs while attending the Commons, the only known occasion in Henry VI’s reign when an MP for the borough who was a resident burgess (rather than a gentleman outsider) agreed to forgo his wages.
It was perhaps during his fifth term as bailiff that Wynter pursued an action of his own in the Chancery. He brought his bill, of about 1470, against Thomas Ellis† of Norwich and (Sir) Thomas Brewes*. It concerned a dispute between him and Ellis, at whose suit he had been arrested at Stourbridge fair near Cambridge in September 1468. The quarrel had gone to arbitration but, owing to its complexity, the arbiters, John Sulyard*, Richard Yaxley and Roger Aylmer, had failed to make an award by the following November, as originally intended. The parties had subsequently agreed to cancel the bonds of arbitration (bearing a £100 penalty) which they had made out to each other, to set 2 Feb. 1469 as a new date for the award, to accept James Hobart† as an additional arbiter and to replace Brewes, the original umpire, with William Harleston. Despite this agreement, Ellis had failed to enter a new bond of arbitration with Wynter and Brewes had taken it upon himself to make an award in which he had ordered Wynter to pay Ellis 55 marks and costs of 100s. by 25 Mar. Although the bill, intended to bring Ellis and Brewes to account for their actions, gives Wynter’s version of events, it is supported by a copy of Sir Thomas’s award, dated 29 Jan. 1469 and drawn up on the Brewes manor at Topcroft in Norfolk.
A few years later, Wynter was quarrelling with a fellow burgess, Thomas Denys*. He had leased out a tenement in the parish of St. Nicholas for 6s. p.a. to the latter but by 1473 he was alleging that Denys had failed to pay him this rent.
Wynter remained active in Ipswich affairs until the late 1470s. Several times during that decade he helped to audit the borough’s chamberlains’ accounts (as he had once done nearly 20 years earlier),
