In 1953 Major-General J.P. MacKenzie, CB, DSO, ED, who was Quartermaster-General during 1942-43, donated a trophy called the Major-General John Peter Mackenzie Trophy. This was originally awarded to the RCE militia squadron that had obtained the highest grading for administration and maintenance of its stores and equipment. It is currently assigned to Land Forces Western Area for the Area Engineer’s Evaluation.
As a civilian, John Mackenzie trained as an engineer and worked in his uncle's firm that was building and operating the Canadian Northern Railway. When WWI broke out he was commissioned Lieutenant in the Fort Garry Horse but, impatient for action, he transferred to the 8th Canadian Infantry Battalion. He served in France from 1915 in line and staff positions.
During a counter-attack at Mont Sorrel on 4 August 1916, he was wounded while leading a wire cutting party but successfully completed his mission and withdrew the other wounded survivors of his section. His gallantry was recognized in the New Year Honours of 1917 when he was awarded the DSO. The first bar to his DSO was awarded for conspicuous gallantry and devotion to duty. He had shown very fine judgement and ability in handling his Battalion during an attack at Arleux en Gevill, 28 April 1917, the success of which was largely due to his quick grasp of the situation. He later made three personal reconnaissances under intense fire to obtain information for the Artillery, and his reports were accurate and of great value.
With the reorganization of the Canadian Engineers in 1918, he was selected to command 1st Engineer Battalion. Again he made several daylight reconnaissances under fire, this time to get the information for the selection of bridge crossings. At Douai, he took hold of the situation as the enemy retreated across the Canal de la Sensee and 'supervised the construction of two bridges under heavy fire with perfect coolness... setting a fine example which naturally encouraged all ranks'. Both bridges were built within six hours and largely contributed to the success of the battle as they were the only means of crossing the canal for two days. He was awarded a second bar to the DSO for his actions. The French awarded him the Croix de Guerre for gallantry and his action east of Amiens on 9 August 1918. By the end of the war, he was mentioned in dispatches four times.
He was a brigade-major in HQ 1st Brigade Canadian Engineers. After the war, he was active in a number of militia units, including 6th Field Company in Vancouver. In 1940 he was appointed CRE 2nd Canadian Division Engineers as a lieutenant-colonel and, by 1942 he was Quartermaster General in Canadian Military Headquarters (CMHQ) as a Major General. Between those years he was the first Director of Works in CMHQ and commander of 6 Infantry Brigade overseas. In 1943, he became Inspector General Military Forces Western Area. Upon retirement in 1940, Major General MacKenzie was made a CB. Between 1948-60 he was Honourary Colonel of the 7th Field Engineer Regiment.