Mair was born at Lanark, Upper Canada, to Margaret Holmes and James Mair. He attended Queen's University but did not graduate. On leaving college, he became a journalist.[1] In Ottawa in 1868, Mair was introduced by civil servant and writer Henry Morgan to young lawyers George Denison, William Foster, and Robert Haliburton. "Together they organized the overtly nationalistic Canada First movement, which began as a small social group."[1] Mair "represented the Montreal Gazette during the first Riel Rebellion, and was imprisoned and narrowly escaped being shot by the rebels."[2] Mair was a Freemason[3] Mair "was an Officer of the Governor-General's Body Guard during the second Riel rebellion in 1885, and was later employed in the Canadian civil service in the West."[2] He died in Victoria, British Columbia.