He was one of many Salvationists who gained prison sentences for conducting street marches: in McKenzie's case, a week of incarceration in Charters Towers, Queensland, with his comrade, Lieutenant Morrison.

McKenzie, who served in various appointments, including a stint on the War Cry magazine staff, is better known as a pioneering chaplain to the 4th Battalion of the Australian Infantry in the First World War.
He later gained the high rank of commissioner in The Salvation Army, serving as a territorial commander for the Australia Southern Territory. ‘Fighting Mac’, as he was known to the troops, was awarded the Military Cross for his personal bravery and spirit of sacrificial service.