He was Member of Parliament for Elgin Burghs from 1747 to 1754, and carried bills for the abolition of heritable jurisdictions, wardholding and for annexation of forfeited estates to the Crown.
[2] At a by-election in February 1747 Grant was returned to parliament as member for the Elgin Burghs, and on 1 April 1747 was "added to the gentlemen who are appointed to prepare and bring in a bill for taking away and abolishing the heretable jurisdictions in … Scotland".
[5] This important measure of Scottish reform was subsequently carried through both houses and passed,[6] as well as another bill, which had been introduced by the lord advocate and the English law officers, for the abolition of ward holding.
Grant died at Bath on 23 May 1764, aged 63, and was buried on 7 June following in the aisle of Prestonpans Church, Haddingtonshire, where a monument in the churchyard was erected to his memory.
[10][11] Grant is said to have written The occasional Writer, containing an Answer to the second Manifesto of the Pretender's eldest Son, which bears date at the Palace of Holyrood House, 10 October 1745; containing Reflections, political and historical, upon the last Revolution, and the Progress of the present Rebellion in Scotland,' London, 1745, 8vo.
[12] Tytler speaks highly of his integrity, candour, and "winning gentleness", and says that his "conduct in the adjustment of the claims on the forfeited estates merited universal approbation".