Robertson was a son of the manse. On his mother’s side her father and grandfather were ministers, the latter being a merchant’s son. His father was minister of Ratho for 42 years until his death in 1802 and his eldest brother served Livingston nearly as long, though when he was in Parliament Alexander attempted, unsuccessfully, to secure a better crown living for him. His brother John died on his way to India in 1795, intending to be a surgeon in the East India Company service, and it appears that Alexander too was on the civil establishment, though he is omitted in the lists.
In 1818 he was returned at Grampound after a contest and held his seat until the disfranchisement of the borough. He did not speak before 1820, though later he became an able and well-informed spokesman on financial and commercial affairs. He voted with the minority on the Windsor establishment, 22 Feb. 1819, on the Marriage Act amendment bill, 26 Apr., on the sinking fund motion, 13 May, and the foreign enlistment bill, 21 June. He died 17 Dec. 1856 at Hoebridge Place, Woking, where he had resided some 30 years.
