Shoulder title The Irish Regiment of Canada 5th Canadian Armoured Division (canvas)

Details from the regiment were placed on service on 26 August 1939 and then placed on active service on 1 September 1939 as the Irish Regiment of Canada (Machine Gun), CASF (Details), for local protection duties. Those details called out on active service disbanded on 31 December 1940.

The regiment mobilized the Irish Regiment of Canada (Machine Gun), CASF for active service on 24 May 1940. It was redesignated as the Irish Regiment of Canada, CASF on 12 August 1940; and as the 1st Battalion, The Irish Regiment of Canada, CASF on 7 November 1940. It embarked for Great Britain on 28 October 1942. It landed in mainland Italy on 10 November 1943, as part of the 11th Infantry Brigade, 5th Canadian Armoured Division. Between 20 and 27 February 1945, the battalion moved with the 1st Canadian Corps to North-West Europe as part of OPERATION GOLDFLAKE, where it fought until the end of the war. The overseas battalion disbanded on 31 January 1946.

The 53rd Field Battery mobilized as the 53rd Field Battery, RCA, CASF on 1 September 1939. On 1 June 1940 it amalgamated with the 26th Field Battery, RCA, CASF and was redesignated as the 26th/53rd Field Battery, RCA, CASF. On 1 January 1941 this amalgamation ceased and it was redesignated as the 53rd Field Battery, RCA, CASF and as the 53rd Light Anti-Aircraft Battery, RCA, CASF the same day. It provided light antiaircraft artillery support as part of the 11th Light Anti-Aircraft Regiment, RCA, CASF, in Great Britain. The overseas battery disbanded on 1 March 1944.