Referred to by Boswell as young Graham of Gartmore he is probably identical with the Scottish politician and poet, the 6th of Gartmore, 15th of Ardoch, son of Nicol Graham, 5th of Gartmore, and Margaret Cunnigham (1705-1789). Married twice, firstly to Anne Taylor, secondly to Elizabeth Buchanan, daughter of Thomas Buchanan of Spittal and Leny.
Graham was sometime Receiver-General in Jamaica, Rector of Glasgow University (1785-1787) and was elected MP for Stirlingshire in 1794. He added the Cunningham to his name upon the death of his relative John Cunningham, 14th Earl of Glencairn, in 1796.
Boswell "strolled about with young Graham of Gartmore" in London on June 18, 1763. Young Graham was 27-28 years old at the time, so Boswell was probably just referring to him in this way to distinguish him from his father.