On May 15, 1924, the South Saskatchewan Regiment was divided into five regional battalions, the Moose Jaw Battalion continuing with the name “South Saskatchewan Regiment.” A further reorganization of the militia on September 15 of that year saw the battalion re-designated The King's Own Rifles of Canada (KORC). The KORC was re-designated The King's Own Rifles of Canada (MG) on December 15, 1936 when it absorbed B Company, 12th Machine Gun Battalion, Canadian Machine Gun Corps. The outbreak of World War II found the King's Own Rifles of Canada (MG) critically short of equipment, to the point where the influx of volunteers practiced drill and performed sentry duty carrying wooden cutouts in the shape of rifles.
For the first 29 months of World War II, the KORC continued as a reserve unit while it waited to be mobilized. As the possibility of mobilization seemed more and more remote, many of its members transferred to other units that had already been mobilized for war. Units such as Moose Jaw's 77th Field Battery, Royal Canadian Artillery (RCA), which was mobilized in 1939 for service as part of the 3rd Field Regiment, RCA, recruited large numbers of soldiers from the KORC. The first battalion KORC was eventually mobilized on January 29, 1942, for service with the 8th Canadian Division, 14th Infantry Brigade. Upon mobilization the name reverted to The King's Own Rifles of Canada. The 1st Battalion was assigned to coastal defense duties in British Columbia until it was demobilized on March 30, 1946. The battalion trained in Nanaimo; two companies were later deployed to serve with the Prince Rupert defense force.
Tradition has it that elements of the 1st Battalion also served in the Aleutian Islands, off Alaska's coast: as two of the Aleutian Islands had been temporarily occupied by the Japanese prior to the Battle of Midway, a combined Canadian and American force was deployed to remove them from these islands. A 2nd (Reserve) Battalion, KORC, served in the Reserve Army throughout the war. The King's Own Rifles of Canada became an armoured unit on April 1, 1946, when it was redesignated The 20th (Saskatchewan) Armoured Regiment. The 1st Battalion, KORC, perpetuated the 46th Battalion, CEF; and the 2nd (Reserve) Battalion, KORC, perpetuated the 128th Battalion, CEF.