Dalrymple was born, probably at Edinburgh, some time in 1720, and died in London on 13 October 1789. His father was George Dalrymple, a younger son of the 1st Earl of Stair. He was educated privately and then studied law at Edinburgh, becoming an advocate of the Scottish bar in 1741. He then purchased a captaincy in the army, serving until 1745 when he attempted to inherit the title of Earl of Stair from his uncle, the 2nd Earl.
From The Biographical Dictionary of British Economists in Oxford Reference.