Geary became a man of Kent through his mother. His father was an unsuccessful ministerial candidate at Rochester in 1768. Geary too was defeated at his first attempt, at Maidstone in 1784. Soon after inheriting, he offered for the county encouraged by Lord Romney, who noted that his affairs were in a ‘very flourishing way’. Because he had resigned his yeomanry troop in 1795 out of opposition to Pitt’s legislation against sedition, he had been ‘represented as hostile to administration’, but this he was at pains to deny, claiming to support the war against revolutionary France. Moreover, he owed his return to a clandestine understanding with the ministerial Member Knatchbull, which ousted the Whig Member Filmer Honywood. He bore the brunt of expenses, amounting, it was said, to nearly £20,000 and paid for his success by selling his Surrey property to Richard Brinsley Sheridan for £12,384.
In the House Geary took an independent line. He first spoke on the unsuccessful petition against his return, 28 Nov. 1796. He approved the militia augmentations, 13 Dec., but joined opposition on the stoppage of payments by the Bank, 1 and 9 Mar. 1797; and although he opposed a county address against ministers on 19 Apr., called on Fox to delay a censure on the naval mutiny, 10 May, and opposed Grey’s reform motion, 26 May, he admitted that he was a reformer, in favour of election by ballot and of a reduction of expenses by the creation of convenient, one-Member constituencies. He suggested that the franchise be extended to all ratepayers of £10 or £20 p.a. He was a critic of the Whig secession. On 7 Nov. 1797 he supported Tierney’s motion against the expense of the third secretaryship of state. He supported Pitt’s triple tax assessment, 4 Jan. 1798, despite his wish for relief from the farm horse tax for small farmers (28 Dec. 1797). He thought that volunteers for home defence should be encouraged by limiting the time and territory of their services, 30 Mar. 1798. He opposed the land tax redemption bill on principle, 4 Apr. Conceding that it was an emergency measure, he still voted against it on 18 May. On 19 Dec. he objected to the tacking on of extra clauses to the income tax bill after its third reading but, assured by the Speaker that this was in order, had to confine his objection to one of them. He favoured union with Ireland, 14 Feb. 1799. He joined opposition in favour of a call of the House, 22 Jan. 1800, for inquiry into the failure of the Helder expedition, 10 Feb., and on the effects of the Act of Union on parliamentary representation, 25 Apr. For the remainder of that Parliament local questions preoccupied him in debate. As representative for west Kent he campaigned for a better county gaol at Maidstone against opposition from the western division of the county, which thwarted him in 1800 but gave in a year later. He voted with the minorities for inquiry into the Ferrol expedition, 19 Feb. 1801, for Grey’s censure motion, 25 Mar., and for Tierney’s motion, 22 Apr. Like his colleague he was placed on the East India judicature committee, 9 Dec. 1801.
Geary owed his re-election in 1802, when he and Knatchbull received the blessing of the Addington ministry, to a push against Knatchbull by Filmer Honywood’s friends. Little credit was given to his denial that he had solicited it. He was aided by subscription and paid less than his share of Honywood’s bills. His tendency to opposition increased.
Geary was returned for Kent faute de mieux in 1812 when, on the resignation of their Member William Honywood, the Whigs could not produce a candidate. He had meanwhile refurbished his reputation as a reformer by taking the lead in promoting a county reform meeting in October 1810 and by publishing his ideas on the subject in the Maidstone Journal in a letter of 4 Dec. In 1811 he was courted by but did not join the Friends of Constitutional Reform, but in 1812 became a founder member of the Hampden Club for reform. Lord Thanet quoted him as styling himself ‘a reforming Tory’.