In 1885, during the second Riel Rebellion, Mair served an Officer of the Governor-General's Body Guard. He worked as a civil servant in the Canadian west, and, in 1899, was appointed as secretary to the Métis Scrip Commission. He travelled thousands of miles through the northwest, and kept a journal of his experiences which contains historical details about the treaty negotiations, and about the native and Métis people and places of the time. However, "Mair’s prose, and the reaction to it, obscured his road work, which drew more resentment."