From this privileged social position, Morris was educated in Canada and Scotland and worked for three years at the Montreal firm of Thorne and Heward.

In 1858, he predicted a coming federation of the British North American colonies in a work entitled Nova Britannia, which sold 3,000 copies in its first ten days of publication.

He also wrote on academic matters and developments in the Presbyterian church in Canada, of which he was a prominent member (becoming a ruling elder of its synod in the 1850s).

He ran as a Liberal-Conservative in the riding of Lanark South in Canada West, supporting the government of George-Étienne Cartier and John A. Macdonald.

He was appointed Minister of Inland Revenue on November 16, 1869, and served as a competent if not prominent member of the Macdonald ministry for the next three years.

Morris maintained Archibald's policy of conciliation among the various factions in Manitoba, and unsuccessfully attempted to establish a local police force to preserve law and order in the region.

He was formally sworn in as the official Lieutenant Governor on December 2, and attempted to accelerate the settling of Métis land claims in the province.

Manitoba's government was still in a developing state when Morris became Lieutenant Governor, and he continued Archibald's practice of serving as the province's de facto Premier.

When the council twice rejected bills that would have resulted in its demise, Morris intervened by offering recalcitrant councillors lucrative government positions elsewhere.

He was defeated by Canadian Pacific Railway spokesman and Independent Conservative Donald A. Smith by 555 votes to 546, and subsequently returned to Ontario again.

Later in 1878, Ontario MLA Matthew Crooks Cameron was appointed as a judge, and the provincial seat of Toronto East became vacant.