8th Bart of Luss (1773-). Son of Sir Ludovick Grant (1707-1773) and Margaret Ogilvy (d. 1757). Married Jane Duff in 1763.
Grant was educated at Westminster School, London and at Christ's College, Cambridge. He succeeded his father as Member of Parliament for Elginshire in 1761, a seat he held until 1768, and from 1790 to 1795 was MP for Banffshire, succeeding James Ferguson.
James Grant died at the family seat of Castle Grant on February 18, 1811. He was succeeded by his son, Lewis Alexander, who later that year also succeeded his second cousin James Ogilvy as 5th Earl of Seafield.
Boswell met a Mr. Grant, son to Sir Ludovic at Lady Frances Erskine's on November 29, 1762.