Les Fusiliers Mont-Royal originated in Montreal, Quebec on 18 June 1869 as The Mount Royal Rifles. It was redesignated as the 65th Battalion, Mount Royal Rifles on 5 November 1869, as the 65th Regiment "Mount Royal Rifles" on 8 May 1900 as the 65th Regiment "Carabiniers Mont-Royal" on 1 August 1902, as Les Carabiniers Mont-Royal on 29 March 1920, as Les Fusiliers Mont-Royal on 15 April 1931, as the 2nd (Reserve) Battalion, Les Fusiliers Mont-Royal on 7 November 1940 and finally as Les Fusiliers Mont-Royal on 15 November 1945.

The regiment mobilized the Les Fusiliers Mont-Royal, CASF for active service on 1 September 1939. It was redesignated as the 1st Battalion, Les Fusiliers Mont-Royal, CASF on 7 November 1940. It embarked for garrison duty in Iceland with "Z" Force on 1 July 1940. On 31 October 1940 it was transferred to Great Britain. The regiment took part in OPERATION JUBILEE, the raid on Dieppe on 19 August 1942. It returned to France on 7 July 1944, as part of the 6th Infantry Brigade, 2nd Canadian Infantry Division, and it continued to fight in North-West Europe until the end of the war. The overseas battalion was disbanded on 15 November 1945.