[1] Montrose was Member of Parliament for Richmond from 1780, and for Great Bedwyn from 1784 to 1790, when he succeeded his father in the dukedom.

According to Robert Bain, Scotland can thank him for the repeal in 1782 of the Dress Act 1746 prohibiting the wearing of tartans.

Graham was a very effective member of the House of Commons, especially when speaking on Scottish topics.

Early in his career as a minister under William Pitt the Younger, Graham was attacked in the Rolliad: Montrose was twice married.

They had seven children: Montrose died at Grosvenor Square in December 1836, aged 81, and was succeeded in the dukedom by his son, James.