MacCarthy, Donogh (1668–1734), 4th earl of Clancarty , soldier and Jacobite, was born in Blarney, Co. Cork, only son of Callaghan MacCarthy (qv) (second son of Donough MacCarthy (qv), 1st earl) and Elizabeth, daughter of George Fitzgerald (qv), 16th earl of Kildare. After the death of his father (21 November 1676) his devout protestant mother put the young earl, who even at a very young age had acquired a reputation for being wild and irresponsible, under the care of Dr John Fell, dean of Christ Church and bishop of Oxford. However he was lured to London by his uncle Justin, later Viscount Mountcashel (qv), and – with the connivance of Charles II – was married at the age of 16 in Westminster abbey (31 December 1684), without his mother's consent, to Elizabeth, second daughter of Robert Spencer, 2nd earl of Sunderland, secretary of state; his bride may have been three years Clancarty's junior.
MacCarthy set out for Ireland with his uncle Mountcashel, and on the succession of James II (qv) (1685) he received a commission as captain of the cavalry and converted to catholicism. In March 1687 he became embroiled in a controversy resulting from the death of William Harris, a butcher from Mallow, Co. Cork, who had been tossed in a blanket by a number of soldiers in the earl's regiment, allegedly because of his whig principles or his refusal to hand over his horse for the king's service. Harris's widow issued a waiver exonerating Clancarty from any part in her husband's death on payment of £100 sterling, but later retracted and pressed her case for compensation, which culminated in the grant of 721 acres (292 ha) of Clancarty's huge estate, the greater part of the barony of Muskerry, then valued at £60,000.
In March 1689 he received King James II on his arrival at Kinsale and was appointed lord of the bedchamber, colonel of the 4th Regiment of Foot (subsequently ‘Clancarty's’), and commander of the Jacobite army in Munster. Although still under age he took his seat in the Irish house of lords in the 1689 parliament. He took command of a troop of horse and gained such a reputation for cruelty that the inhabitants of Bandon, Co. Cork, refused him admittance. He later joined his uncle in the operations in the siege of Derry and led a ferocious and almost successful assault on Butcher's Gate, which is documented in every contemporary memoir of the siege.
After the battle of the Boyne he was posted for garrison duty in Cork. Captured and sent to the Tower of London after Cork fell to Marlborough (qv), he escaped to Saint-Germain in France in April 1694, leaving as a practical joke on his jailers a wig block in his bed, with the inscription ‘The block must answer for me.’ He commanded the second troop of horse guards in the service of James II and Louis XIV until the treaty of Ryswick (1697), while retaining his post as a gentleman of the bedchamber. In 1698 he secretly returned to England to visit his wife, after his troops were disbanded, but was betrayed by his brother-in-law Charles, Lord Spencer, and was returned to the Tower. He was finally pardoned through the intercession of Lady Russell and received an annual pension of £3,000, dependent on his leaving the kingdom for good. His vast estate – the largest single estate forfeited by an Irish Jacobite – was confiscated under the Williamite settlement. Lord Woodstock, son of William Bentinck (qv), duke of Portland, was granted 135,820 acres, and much of the rest was purchased by the Hollow Blades Company. Clancarty removed himself from William's (qv) dominions and became a lord of the bedchamber to the Old Pretender, James III in August 1707. He derived a modest income from the flotstam and jetsam that accumulated at an island that he bought off Hamburg. He died on 19 September 1734 at Praals-Hof, near Hamburg. His beloved wife died in 1704, survived by three children: Robert, titular Viscount Muskerry and titular 5th earl of Clancarty, prominent Jacobite exile and companion of Prince Charles Edward Stuart; Justin, an officer in the Neapolitan army; and Charlotte, who married John West, 7th Lord Delawarr.