His father, Roderick McKenzie, was a founder and for years a prominent member of the farmers' movement in Western Canada.
[2] Although he had no prior experience in electoral politics, McKenzie was appointed to John Bracken's government on October 22, 1928 as Minister of Mines and Natural Resources.
On November 10, 1928, he was elected to the Manitoba legislature in a by-election in the constituency of Lansdowne, replacing former premier Tobias Norris.
McKenzie ran as a "Liberal-Progressive",[1] and was endorsed by both Bracken's Progressives and the local branch of the Manitoba Liberal Party.
McKenzie was easily re-elected in Lansdowne, and appointed Minister of Agriculture and Power Commissioner after a cabinet shuffle on May 27, 1932.