George William Campbell succeeded his father (who was a Member of Parliament for Glascow) as 6th Duke of Argyll in 1806. His mother, Elizabeth, daughter of John Gunning and Hon. Bridget (daughter of 6th Viscount Bourke of Mayo) of Castle Coote, county Roscommon [Ireland], was the widow of the 6th Duke of Hamilton. She was created Baroness Hamilton in 1776 and died in 1790. Thus on the death of his half-brother, the Duke of Hamilton, in 1799, George inherited the barony of Hamilton conferred on his mother. He Served from 1790-96 as a Member of Parliament for St. Germain, as Lord Lieutenant for county Argyll from 1800 to his death in 1839, as Keeper of the Great Seal of Scotland from 1827-39, and as Lord Steward of the Household from 1833-34 and 1835-39. On 29 November 1810, the Duke married Caroline Elizabeth [d. 1835], formerly the wife of the 1st Marquess of Angelsey, and daughter of the 4th Earl of Jersey. They had no children, thus the Duke was succeeded by his brother, John Douglas Edward Henry, as 7th Duke of Argyll.