Son of John Hamilton and Margaret Montgomery. Married to Lillias Montgomerie (1743-1827),1 with whom he had several children, including John Hamilton, who succeeded his father as Laird of Sundrum, and Alexander West Hamilton (d. 1837), who inherited the Belleisle estate in Ayr from his uncle Hugh Hamilton of Pinmore (1746-1816).
- 1Lillias Montgomerie was a sister to Hugh Montgomerie of Coilsfield, who succeeded to the title of 12th Earl of Eglinton upon the death of his third cousin, Archibald Montgomerie (d. 1796), the 11th Earl.
Life with Boswell
Boswell introduced Hamilton to Dr Johnson on August 15, 1773, in Edinburgh. He described Hamilton as "my neighbour in the country".