Mills’s ancestors included members of the Forster family, aldermen of Durham in the eighteenth century. His father was at one time in business in that city as a wine merchant, in partnership with one of his Forster kinsmen, and by 1787 he was senior partner in the Durham banking house of Mills, Hopper and Company, which ceased trading in 1802; by then he had acquired some land and a house at Willington in the parish of Brancepeth, near Bishop Auckland.
The duke of Wellington’s ministry listed Mills as one of their ‘foes’, and he duly voted against them in the crucial civil list division, 15 Nov. 1830. He is not known to have spoken in debate, and he vacated early in 1831 to accommodate Sir William Horne, the Grey ministry’s solicitor-general.
