Career
Born in Melbourne, he was a teacher before entering politics. In 1972, he was elected to the Australian House of Representatives as the member for Diamond Valley, defeating Liberal Member of Parliament Neil Brown. As a backbench Member in 1973 McKenzie, together with fellow Labor Member Tony Lamb, introduced the Medical Practice Clarification Bill which, if passed, would have allowed abortion in the Australian Capital Territory.
The Bill was defeated after a conscience vote on 10 May 1973 by 98 votes to 23.
McKenzie held the seat until his defeat by Brown in 1975.