Wynn appeared in the law lists from 1797 as a conveyancer and equity draftsman; by 1805, when his sister-in-law Viscountess Perceval applied to Pitt for a Welsh judgeship for him, he was practising on the North Wales circuit and he continued to do so while in Parliament. He wrote to Lord Grenville, 20 Nov. 1806, asking to succeed his dying uncle Thomas, 1st Baron Newborough, to the office of prothonotary and clerk of the crown in North Wales which had ‘been held for many years by our family and latterly in succession by my father and uncle. In point of emolument it is of little or no consideration to me, comparatively with the anxiety to have continued in the family an office which has so long been held by it’. In fact his elder brother Thomas succeeded to it.1PRO 30/8/166, f. 68; CJ , lxiii. 186; Fortescue mss; W. R. Williams, Gt. Sessions in Wales, 123.
Wynn had joined the Whig Club, with other members of his family, in 1789, but seceded after the outbreak of war. Deprived by family quarrels of the provision made for him in his grandfather’s will and of the electoral interest the Wynns had possessed at Caernarvon, he nevertheless sat briefly for the borough of Westbury on the Earl of Abingdon’s interest, purchased on that occasion by Lord Harewood, a Yorkshire neighbour of Wynn’s brother. No speech or vote against administration is known and Wynn, who had been expected to do so a few months after his election, vacated his seat not long before his death on 23 Apr. 1809.2Trans. Caern. Hist. Soc. ix. 33; xx. 86; Wellington mss, Long to Wellesley, 11 May [1807]; Trans. Carm. Antiq. Soc. viii. 50.