He was the only son of
Francis Charteris, second son of
James Wemyss, 5th Earl of Wemyss. The fifth Earl's eldest son
David Wemyss, Lord Elcho had been
attainted for his part in the
Jacobite Rising of 1745 so after the Earl's death in 1756
the earldom became forfeit. Charteris was elected to Parliament for the
Haddington district of burghs in 1780. From 1784 he was in opposition to the government of
William Pitt the Younger. In 1787 Charteris' uncle Lord Elcho (who but for his attainder would have been 6th Earl of Wemyss) died. As Charteris' father had not been attainted himself, he assumed the title as 7th Earl of Wemyss, with Charteris himself assuming the subsidiary title
Lord Elcho. At the time
eldest sons of Scottish peers were not allowed to represent
Scottish constituencies in Parliament, and after a debate on the matter Charteris had to vacate his seat. Although it was later established that the Earldom of Wemyss remained forfeit and his father was not after all a Scottish peer, Charteris did not attempt to re-enter Parliament. Charteris died on 20 January 1808 at
Amisfield House,
East Lothian, and was interred at
St Mary's Collegiate Church, Haddington. ==Marriage and issue==