In 1835 he became Governor General of British North America (also Lieutenant-Governor of Lower Canada), and commissioner in the Royal Commission for the Investigation of all Grievances Affecting His Majesty's Subjects of Lower Canada. He was instructed to appease the reformists, led by Louis-Joseph Papineau, without giving them any real power. Gosford attempted to distance himself from his predecessor, Lord Aylmer, who had exacerbated the hostility of French-Canadians to the British administration. Gosford officially established the Diocese of Montreal in 1836, though it had been unofficially created a few years before. In August of that year Gosford dissolved the Legislative Assembly when they refused to pass his budget.
In November, Lord Gosford learned of the planned Lower Canada Rebellion and had many of Papineau's followers arrested, although Papineau himself escaped to the United States. The next month, he issued a reward for the capture of Papineau, and declared martial law in Lower Canada.
Lord Gosford resigned in November 1837 and returned to Britain the next year. His eventual successor, Lord Durham, implemented the Union Act in 1840 (which Lord Gosford unsuccessfully argued against). He died in 1849.
