When the First Canadian Army was formed overseas in 1942, Lieutenant-General McNaughton's aim was to keep the Canadian Army unified to lead the cross-channel assault on northwest Europe. Two brigades of the 2nd Canadian Division led the ill-fated Dieppe Raid in 1942. Aside from this endeavour, the Army did not see combat until July 1943. In 1943, because the Canadian government wanted Canadian troops to see action immediately, the 1st Canadian Infantry Division, 1st Canadian Armoured Brigade, and 5th Canadian Armoured Division were detached from the Army for participation in the Italian Campaign.
In early 1944, the 3rd Canadian Infantry Division and 2nd Canadian Armoured Brigade were also detached to British I Corps to participate in the assault phase of the Normandy landings. II Canadian Corps became operational in Normandy in early July 1944, as the 2nd Canadian Infantry Division landed. The First Canadian Army headquarters did not itself arrive in Normandy until mid-July, becoming operational 23 July 1944 just prior to 4th Canadian Armoured Division arriving on the Continent.
First Canadian Army generals in Hilversum
, the Netherlands
, on May 20, 1945 Seated from left: Stanisław Maczek
(Polish Armoured Division), Guy Simonds II Canadian Corps
, Harry Crerar
First Canadian Army, Charles Foulkes I Canadian Corps
, Bert Hoffmeister 5th Canadian (Armoured) Division
; Standing from left: Ralph Keefler 3rd Canadian Infantry Division
, Bruce Matthews 2nd Canadian Infantry Division
, Harry Foster 1st Canadian Infantry Division
, Robert Moncel
(for Chris Vokes 4th Canadian (Armoured) Division
, S.B. Rawlins, 49th British Division
The Army proper first went into action in the Battle of Normandy and conducted operations at Falaise (e.g. Operation Totalize, Operation Tractable) and helping close the Falaise pocket. After reaching the Seine, the objective of the first phase of Operation Overlord, the Army moved along the coast towards Belgium, with the Canadian 2nd Division entering Dieppe at the beginning of September. The critical Battle of the Scheldt in October and November opened Antwerp to Allied shipping.
The First Canadian Army held a static line along the river Meuse (Maas) from December through February, then launched Operation Veritable in early February. By this point the Army, besides the II Canadian Corps, contained nine British divisions. The Siegfried Line was broken and the Army reached the banks of the Rhine in early March.
In the final weeks of the war in Europe, the First Army cleared the Netherlands of German forces. By this time the First Division and Fifth (Armoured) Division as well as First Armoured Brigade and the 1st Cdn AGRA had returned to the Army during Operation Goldflake and for the first time, both the I Canadian Corps and II Canadian Corps fought under the same Army commander.