Mills entered his uncle and namesake’s London business, through him secured his entree to the East India Company directorate and inherited his property. On his marriage he retired from business and, after residing at Meriden Hall, Warwickshire, for a few years, purchased the Bisterne estate (1792).
Mills became Member for Coventry, where he had property, after a contest for a vacant seat in 1805. He was sponsored by his cousin William Wilberforce Bird and made much of his local origins. This commended him to the Blue (independent) party who thus returned both Members. He voted with the majority in favour of criminal prosecution of Melville, 12 June 1805, and was in July listed ‘doubtful Sidmouth’, with his brother Charles. Like him, he voted for the Grenville ministry’s repeal of Pitt’s Additional Force Act, 30 Apr. 1806, after appearing in the minority on the affairs of India on 21 Apr. He was absent on leave for two weeks from 25 Mar. 1807 and the Whig calculator Fremantle ventured to list him ‘doubtful’ after the general election that year, in which he faced a contest. The Marquess of Buckingham corrected this: Mills ought to be counted ‘with us’, and he probably voted with them on Lyttelton’s motion of 15 Apr.
In October 1811 a critic of the current representation of Coventry had this to say:
the independent interest are equally disgusted with Mr Mills ... an inefficient character having never rendered a single service to the town—or any individual who has applied to him—and never spoke in the House of Commons but once since his return to Parliament and then at the suggestion of a violent Pitt faction in the corporation for the purpose of flattering Mr Perceval and reflecting on the proceedings of one of the most numerous and respectable meetings ever witnessed in Coventry, exclusive of which Mr Mills paralyses everything which our other representative P[eter] Moore Esq., might be inclined to attempt in favour of the independent interest ...
Whitbread mss W1/1902.
Despite this, Mills left little doubt as to his political inclinations. He voted against McMahon’s sinecure, 24 Feb. 1812, for Turton’s censure motion, 27 Feb., and paired against the orders in council, 3 Mar. He voted for Williams Wynn’s constitutional motion, 14 Apr., for Catholic relief, 24 Apr., for sinecure reform, 4 May, and for the abolition of Lord Arden’s sinecure, 19 June 1812. When at the ensuing election he decided to retire rather than face a contest, his Hampshire neighbour George Rose assured the Treasury that Charles Mills (who remained in the House) was ‘by no means so decided as his brother Wm.’ in opposition.
Mills died 20 Mar. 1820, leaving his sons John and Charles, both of whom entered Parliament, £10,000 each. They also benefited from the death without issue of their uncle Charles, through whom his namesake nephew became a partner in Glyn Mills Bank.
