Dunscomb stood for election in first general election in 1841, for the riding of Beauharnois, and was elected to the Legislative Assembly of the new Parliament. He was a Government supporter, who favoured the union of Lower Canada and Upper Canada into a single province. He generally supported the British Governor-General, Lord Sydenham.[5]
In the second session of the Parliament, held in 1842, there was a major re-organisation of the ministry, when the new Governor-General, Sir Charles Bagot, appointed two strong reformers to the Executive Council, Robert Baldwin from Canada West, and Louis-Hippolyte Lafontaine from Canada East. Dunscomb was a co-mover of a resolution, along with John Simpson, expressing satisfaction with the new Council. The resolution stated that: "it was absolutely necessary to invite that large portion of our fellow subjects who are of French origin to share in the government of this country." The motion passed, although heavily amended.[5]
On July 15, 1842, Dunscomb was appointed Warden of Trinity House in Montreal. He resigned his seat in the Assembly on October 8, 1842.[6][7]
He later served as customs collector at Quebec City and as Customs Commissioner for the Province of Canada. He was the author of Provincial Laws of the Customs and Canadian Custom House Guide, both published in 1844.[6]
^There is some uncertainty about the dates of his birth and death. The biography given by the National Assembly of Quebec states he was born before 1821, and died around 1875. The published family history gives precise dates of February 23, 1804 and December 16, 1891. Those dates are used here.
^Dunscomb spelt his name differently from his father, without an "e".