George Macartney was born on 14 May 1737 at Lissanoure, Ireland, and educated at Trinity College, Dublin, graduating M.A. in 1759. He then travelled extensively on the Continent and then made the acquaintance of Stephen Fox, brother of Charles James Fox. In 1764 he was knighted and went as envoy extraordinary to St. Petersburg, where he concluded a commercial treaty with Russia. He was returned to Parliament for Cockermouth in 1760, but resigned when elected for Antrim in the Irish House of Commons, in view of his becoming Chief Secretary for Ireland, a post he held from 1769-1772.
From 1775-1779 Macartney was Captain-General and Governor of the Cariboo Islands (Grenada, the Grenadines and Tobago). He was at his post in Grenada in 1779 when the island was attacked and captured by the French. Macartney was taken to France as prisoner of war but was soon exchanged. In 1700 he was sent on a confidential mission to Ireland and in the same year was appointed Governor and President of Fort St. George (Madras) by the East India Company. On his journey back to England he called at the Cape of Good Hope in October 1705.
Macartney's next missions of importance were to Pekin (Beijing) in 1792 and Italy in 1795, where he negotiated with Louis XVIII of France, then in exile in Verona. Other honours fall to him; in 1772 he was made K.B., in 1776 Baron Macartney of Lissanoure (Irish peerage), in 1792 Earl Macartney and Viscount Macartney of Dervock in the peerage of Ireland and in 1796 Baron Macartney of Parkhurst, Sussex, and of Auchinleck, Kirkcudbrightshire.
In failing health, Macartney, on 30 December 1796, reluctantly accepted the appointment of Governor of the newly captured colony of the Cape of Good Hope. He arrived there on 4 May 1797 and remained until November 1798 when his health compelled his return to England. Because of his continued ill-health, he refused all further offices offered to him.
Macartney married the Lady Jane Stuart, second daughter of John Stuart, Earl of Bute, but there was no issue of the marriage. He died on 31 May 1806.
In youth Macartney was considered one of the meet handsome and accomplished young men of his day. He had scholarly tastes and possessed a fine library. It has been said of him that no public servant over left office with purer hands