Baron Gustaf or Gustav Ludvigsson Hamilton (late 1650s – 1691), known as the governor of Enniskillen (their chief of defence) in Northern Ireland, was colonel, and de jure friherre of Deserf in peerage of Sweden.
Gustav was born son of Swedish baron Ludvig Malkolmsson Hamilton (died 1662) and his wife lady Anna Karin Larsdotter Grubbe Stiernfelt, daughter of lord Lars Pedersson Grubbe Stiernfelt, sometime Swedish Secretary of State, and his wife Karin Gotskalksdotter.
From father's side, In 1684, the English-held government, fearful of the Mac Sweeney clan, placed a garrison in Doe Castle, County Donegal, commanded by Major Gustavus Hamilton.
In 1689 the town of Enniskillen was subjected to a siege that year by Jacobite troops, during the conflict which resulted from the ousting of James II of England by his Protestant rival, William III of Orange.
After his death in 1691, his wife (Margaret Jones) and children (Andrew and Gustav, both became pastors) continued to live at Monea, but they had to sell the estate in 1704.