MacKenzie enlisted in RAAF Aircrew on the 7th of July 1943.

Having trained on single engine Wirraways, he graduated Sergeant Pilot and was posted to 2OTU at Mildura for operational training. On the 7th of November 1944, while carrying out exercises in the designated low flying area 10 miles due west of the aerodrome, his Kittyhawk A29-195 struck trees and crashed at 1330 Hours. Sergeant MacKenzie was 21 years of age at the time of his death.