Brigadier-General Sir Charles MacCarthy (15 February 1764 – 21 January 1824) was an Irish-born soldier who served in the French, Dutch and British armies, and was a governor of various British territories in West Africa.
He was born in Cork in Ireland, the son of the French émigré Jean Gabriel Guérault and his wife Yvette Parra; he changed his name at an early age to MacCarthy, his mother's maiden name, on the advice of his uncle Thaddeus MacCarthy, a colonel in the Life Guards of Louis XV and later a captain in the 9th Regiment of Foot. He married Antoinette Carpot in 1812, and had one son, Charles; he would be adopted by his uncle, the Comte de Mervé after his father's death, and succeed to that title on his uncle's death as a naturalised French citizen.
At the age of 21, in 1785, he joined the Irish Brigade of the French army, as a sub-lieutenant in the Régiment de Berwick; by 1791 he had attained the rank of Captain, and was serving with the émigré royalist army under Louis Joseph de Bourbon, prince de Condé in Germany. He later served with the army of the Dutch Republic as a volunteer, in Damas' Regiment, from 1793 to 1794, and was wounded in the leg during an action outside Louvain on 15 July 1794.
He subsequently saw service in the Duc de Castries's Regiment of the émigré army, and when the Irish Brigade was reorganised in British pay in late 1794, he was appointed an ensign in the Regiment of Le Comte de Conway (the 6th Regiment of the Brigade), and saw service in the West Indies with the Regiment of Le Comte de Walsh-Serrant (the 2nd Regiment) from 1796 to 1798. Returning from Honduras on the transport HMS Calypso in June 1798 with the grenadier company of that regiment, he was wounded whilst in a day-long action fighting off a French privateer. The Irish Brigade was disbanded as a whole in late 1798.
He received his first British commission on 17 October 1799, when he was appointed to command a company of the 11th West India Regiment, and transferred to a captaincy in the 52nd (Oxfordshire) Regiment of Foot on 15 March 1800. He was appointed a Major in the New Brunswick Fencible Infantry (later the 104th Foot) on 14 April 1804 and remained with them until 1811, when he received a Lieutenant-Colonelcy in the Royal African Corps.