[1] He caught cholera during the epidemic of 1848–1849 and decided to move to British North America for his health.
Cowan joined the Hudson's Bay Company as a doctor and fur trader and, in 1856, he was sent to Moose Factory.
In 1862, he returned to Upper Fort Garry as second-in-command to the governor of Assiniboia, William Mactavish.
Cowan spent the winter under house arrest but is believed to have been sympathetic to Riel's group.
Cowan's journals served as an important record of the early events in the Red River Rebellion.