He entered the House of Commons in 1782 and served as Secretary of State for Foreign Affairs (1791–1801) under William Pitt the Younger. After Pitt’s death he formed the so-called ‘Ministry of all the Talents’ (February 1806–March 1807). Attempts to end the Napoleonic Wars failed, but a bill for the abolition of the British overseas slave trade succeeded, following a resolution introduced by Charles James Fox. A bill to emancipate Roman Catholics, however, was rejected by George III, and Grenville resigned from politics.