Hamilton was a younger son of the Dalrymple clan of jurists, soldiers and politicians, headed by John, 2nd Earl of Stair. A man of vigorous personality and pawky humour, he attached himself to Frederick, Prince of Wales, became an intimate friend of the Grenvilles,
Dupplin, in his parliamentary lists of 1754, counted Hamilton among ministerial supporters connected with Argyll, but in 1755 he followed Pitt into opposition, and supported his Administration 1756-7, when Scottish placehunters sought to make use of his ‘particular friendship and intimacy’ with the Grenvilles.
In the Scottish militia agitation Hamilton took an active but not a leading part; attended the meeting at Ayr on 12 Oct. 1759 to address the King, and was a member of the Commons committee to prepare the bill.
In Ayrshire Hamilton by about 1758 had joined his relations in supporting the Argyll-Loudoun candidate against Archibald Montgomerie, brother of the Earl of Eglintoun, who in retaliation allied himself with Galloway, secured his brother’s return for Wigtown Burghs, and opposed Hamilton’s candidature in Wigtownshire. Hamilton was returned with the backing of Bute, but was obliged to accept a compromise with the Galloway interest, vacated the county seat, and in April was returned for the Burghs.
He supported Bute, and was equally constant to Grenville, who repudiated Garlies’s demand that Hamilton should be excluded from any share in Wigtown Burghs patronage.
Listed ‘doubtful’ by Rockingham in July 1765, Hamilton followed Grenville into opposition and voted against the repeal of the Stamp Act, 22 Feb. 1766. After the formation of the Chatham Administration Grenville believed that Hamilton was still ‘inclined’ to follow him;
From 1766 Hamilton had been seeking another seat. He proposed standing for Ayrshire but was dissuaded by Loudoun.
By his second marriage in 1769 he became connected with his old enemies, the Eglintoun family, but in 1772 wrote to Loudoun roundly denying a rumour that he was ‘an apostate’ to his interest or intended standing for Ayrshire as the Eglintoun candidate: ‘I have no views for myself and am thankful my ambition that way is satisfied.’
He died 12 Feb. 1796.
