Hamilton, Hugh or Hugo (d. 1678), Baron Hamilton of Glenawly , soldier, of Ballygally in Co. Tyrone, was probably the second of three sons of Malcolm Hamilton (qv), archbishop of Cashel by his first wife Mary, daughter of Robert Wilkie of Saughton Hill. The archbishop also had two sons by his second marriage, to Jean Crawford. Some accounts however identify his father as Archibald Hamilton (qv), the preceding archbishop of Cashel.
He entered the Swedish army in 1624, reaching the rank of colonel in 1641, and was ennobled as Baron Hamilton of Deserf in 1654. When his eldest brother Archibald died without issue in 1659 he succeeded to some Irish lands. He returned to Ireland and on 2 March 1661 was created baron of Glenawly in Co. Fermanagh. Between 1663 and 1677 he appears as captain of a troop in a series of lists of Irish army officers, and he was a member of the privy council by 1675.
He had commercial interests in northern Europe, presumably dating from his years in the Swedish service. In 1670 he made a proposal to the English navy commissioners for the supply of masts, acting as agent for those who enjoyed a privilege from the king of Sweden for the export of masts from Riga. In 1671 or 1672 the city of Hamburg paid him substantial compensation for a ship of his which had been burnt on the Elbe.
He died in April 1678. He was married twice: first in 1637 in Stockholm to Margaretha Forath, a native of Scotland and widow of General Baron Williamson Spens, with whom he had one daughter; and second to his cousin Susanna, daughter of Sir William Balfour of Pitcullo in Fifeshire, a parliamentary general in the civil war, and his second wife Isabella. The second marriage produced five children. Two of their three daughters survived to adulthood, and one of their two sons; this was William, who succeeded his father but whose accidental death in February 1681, aged about twenty and unmarried, extinguished the title. Glenawly's wife survived him and was married again, to Henry Mervyn, of Trillick, Co. Tyrone; she died 11 December 1687.
One of Glenawly's half-brothers, Lewis Hamilton (sometimes Ludovick or Louis) also served in Sweden, where he married Anna Catherina Grubbe-Stjernefelt (1631–p.1689). After his death in Gothenburg in 1662 she came to live in Ireland where, as Anna Catherine, Lady Hamilton of Tullykeltyre, Co. Fermanagh she and her eldest son Gustavus (qv) (d. c. 1691) were named in the act of attainder of the Irish parliament of King James (qv) in 1689. Gustavus, who had reached the rank of colonel in the Swedish service, was governor of Enniskillen and was active in the Williamite war effort.
Hugh's younger full brother, Captain John Hamilton (c.1610?–1696), and his wife Jean Somerville had four sons. The eldest, Malcolm Hamilton (1635–99), joined his uncle Hugh in Sweden in 1654; served in the Life Guards of Queen Christina; was naturalised as a Swedish subject in 1664 and was ennobled as Baron Hamilton in 1689. He rose to the rank of major general and governor of Wester-Nowland in 1698, and died at Gothenburg in 1699.
In 1661 he married Christina (1673–1709), daughter of John Maclean of Gothenburg, and widow of Colonel David Sinclair. They had three sons and three daughters; the eldest son, Hugh John or Hugo Johan (d. 1748), succeeded to his father's title and reached the rank of field marshal in the Swedish army in 1734.
In 1680 Malcolm invited his youngest brother Hugh Hamilton (d. 1724) to Sweden, where he reached the rank of general. He married Anna Margaretta (d. 1722), daughter of Hendrick Arfirdssohn. Of their fourteen children, nine sons and two daughters survived infancy; several of the sons served in the armies of Holstein, Sweden and France.
Correspondence of several members of the family survives in Swedish archives and has been microfilmed by the NLI. The British Library's collection of Lauderdale correspondence (Add. MSS 21,113–38) contains some letters by Glenawly.