Montgomery, Hugh (1651–1717), 2nd earl of Mount-Alexander , soldier and politician, was born 24 February 1651 at Newtown, Co. Down, the son of Hugh Montgomery (qv), 1st earl of Mount-Alexander, and his wife, Mary (d. 1655), eldest daughter of Charles Moore (qv), 2nd Viscount Moore of Drogheda. The boy, who had an elder sister and a younger brother, was styled Viscount Montgomery from 1661 and succeeded to his father's title in 1663. His patrimony had been much diminished by his father's misfortunes during the civil war and interregnum, and was encumbered by debt. Official promises of compensation bore little fruit and neither of the marriages made by the young man was materially advantageous. He married first, in 1672, Catherine (d. 1674), eldest daughter of Carey Dillon, earl of Roscommon, and Catherine Dillon (née Werden); and secondly, Eleanor, daughter and co-heir of Maurice Berkeley, 3rd Viscount FitzHardinge, and Anne Berkeley (née Lee). He sold the great bulk of his estates between 1675 and 1679 to his Co. Down neighbour Sir Robert Colville (qv), with whom he was later to have poisonous relations.
A promise in 1671 of a commission as captain of a troop of horse was fulfilled in 1674 and, according to William Montgomery (qv), the family chronicler and his guardian, he was in 1683 made governor of Charlemont and custos rotulorum for Co. Down. In 1685 he received favours from the new king, James II (qv): a seat at the privy council, a pension of £400 p.a., and – acknowledging his devotion to the turf – inclusion as one of the three founding members of a corporation of horse breeders in Co. Down established by royal charter. In January 1687, however, a Francis Meara was commissioned lieutenant to Mount-Alexander by the earl of Tyrconnell (qv), and in June or July 1688 Meara displaced him as captain.
An anonymous letter addressed to Mount-Alexander and found on the street in Comber, Co. Down, on 3 December 1688 alleged that a massacre of protestants was planned for the 9th. The circulation of the letter led to a widespread panic, to which the flight of many protestants from Dublin and the closing of the city gates at Derry were attributed. It also prompted the protestant gentry of Down and Antrim to associate for defence and to elect Mount-Alexander as their general commander in January 1689. An address to William of Orange (qv) elicited commissions for a dozen regiments but no material help. The newly created colonels, in addition to Mount-Alexander, included Sir Arthur Rawdon (qv), Clotworthy Upton (qv), and Clotworthy Skeffington (qv), son of the 2nd Viscount Massarene (qv).
Mount-Alexander did not, however, establish dominance over this group, whose effectiveness was impeded by rivalry and mutual mistrust among the senior officers. Their unsuccessful attempts to disarm Jacobite garrisons in Carrickfergus and Belfast were followed by an encounter with General Richard Hamilton (qv) on 14 March 1689. The protestant forces under Mount-Alexander, trying to stop the advance of Hamilton's forces into Ulster, were routed in an engagement known as ‘the break of Dromore’. He fled to the Isle of Man and ultimately to London, where he remained in discontented and lonely exile until he returned to Ireland in 1691. Diligent attendance at the house of lords from 1692 and the privy council from his reappointment in 1693 probably helped to restore his standing. He was master general of the ordnance, 1698–1705, was appointed brigadier general in 1699, and was one of the lords justices of Ireland, 1702–4. He died 12 February 1717 and was buried at Newtown. He had no surviving children and was succeeded as 3rd earl by his brother Henry (d. 1705).
A letter book of the lords justices, April–August 1702, is in the British Library, Add. MS 37351; selections are printed in S. W. Singer (ed.), The correspondence of Henry Hyde, earl of Clarendon, and of his brother, Laurence Hyde, earl of Rochester (2 vols, 1828).