Lennox, Charles (1764–1819), 4th duke of Richmond and 4th duke of Lennox , lord lieutenant of Ireland, was born 9 September 1764, the eldest son of Lord George Henry Lennox, a general, and his wife, Lady Louisa Lennox Kerr, daughter of the 4th marquess of Lothian; he was apparently born in a barn in Scotland when his mother was on a fishing trip. He was educated privately by a Mr Kempson. Following his father into the army, he joined the Sussex militia and was gazetted captain in 1780. Through the influence of his uncle Charles Lennox, 3rd duke of Richmond, he rose rapidly, and on 26 March 1789 became a captain in the Coldstream foot guards. This angered its commander, the duke of York, the king's son, and his criticism of the appointment drew a swift reply. They fought a duel on 26 May, and Lennox shot off one of York's curls. When Theophilus Swift (qv) wrote a pamphlet criticising Lennox's character, a second duel followed. The controversy cast doubt on Lennox's judgement and he was soon transferred to a regiment in Scotland.
He entered parliament as MP for Sussex (1790–1806), a safe seat given him by his uncle, and supported the ministry of William Pitt. He was brevetted colonel and aide-de-camp to the king in 1795, becoming colonel of the 35th foot in 1799. The death of his uncle, 29 December 1806, led to his succeeding as 4th duke of Richmond. After the Act of Union few prominent noblemen were eager to accept the office of lord lieutenant of Ireland, and after two other dukes had refused the position, Richmond was offered and accepted the duty on 1 April 1807. During his time in Dublin he was a genial, though indifferent, viceroy. A keen sportsman (he was one of the finest real tennis players in England), he organised numerous hunts and horse races to maintain the popularity of the administration, and allegedly spent much of his time drunk; this, and his wife's gambling, were blamed by many for his failings. His first chief secretary was his friend Arthur Wellesley (qv), the future duke of Wellington. Together they opposed any further concessions to the catholics and in 1812 Lennox stated this as a condition of his continuing in Ireland. His appointment ended in August 1813 and he returned to England, before moving to Brussels for financial reasons; he had lived extravagantly in Ireland and was now paying the price. At Brussels he held the famous ball on 15 June 1815 where Wellington learned that Napoleon had outmanœuvred him. Present at Waterloo three days later, according to some witnesses Lennox encouraged a charge of cavalry after midday. On 18 March 1818 the restored King Louis XVIII made him duke of Aubigny in France. On 8 May 1818 Richmond was appointed governor-in-chief of British North America (Canada). There, his anti-catholic record in Ireland and his extreme views created some hostility, but he showed himself to be an able administrator, though a short-sighted politician.
He married, 9 September 1789, Lady Charlotte Gordon, daughter of Alexander Gordon, 4th duke of Gordon; they had seven sons and seven daughters. In summer 1819 he contracted hydrophobia, after being bitten by a fox, and died 28 August.