Acheson sat in the
Irish House of Commons for
County Armagh from 1798 until the
Act of Union in 1801, when Ireland became part of the United Kingdom. Subsequently, he was a Member of the
British House of Commons representing
Armagh to 1807, when he succeeded to his father's Irish titles as Earl of Gosford. He entered the British
House of Lords in 1811 upon being elected an
Irish representative peer. In 1831 he was appointed the first
Lord Lieutenant of Armagh for life, having previously been a
Governor of Armagh since 1805. The new position incorporated the post of
Custos Rotulorum of County Armagh which he also already held. He was also
Colonel of the Armagh Militia from 19 November 1834. He was created
Baron Worlingham in the
Peerage of the United Kingdom in 1835 and thus became a member of the UK House of Lords in his own right. He commissioned Thomas Hopper (1776–1856) to design a new house,
Gosford Castle on his Gosford estate. The house would not be completed until after his death. 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.
Lord Durham, was appointed Governor General in 1838. He produced the
Durham Report which recommended that Lower Canada and Upper Canada be reunited, with
responsible government, which Lord Gosford had unsuccessfully argued against. ==Personal life==