On 30 October 1917 near Passchendaele in Belgium, McKenzie was serving with the 7th Canadian Machine Gun Company, leading a section of four machine guns in support of the PPCLI. Seeing that one of the PPCLI companies was hesitating to advance in the face of a nest of German machine guns positioned on commanding ground, he handed over the command of his section to a non-commissioned officer, and went to rally the men of his old regiment. McKenzie organized an attack and captured the enemy position. However, he very soon realized that this position was itself swept by machine gun fire from a nearby German “pillbox” fortification in a dominant location. Faced with this challenge, McKenzie organized parties to capture the pillbox by attacking its flanks as well as by a frontal assault. He was killed while leading the frontal attack.
For his conduct on this occasion, McKenzie was awarded the Victoria Cross posthumously.