The 50th Battalion CEF was mobilized in Calgary in November 1914, training in Calgary and Sarcee Camp. In June 1915, the first draft of five officers and 200 men left for England where many became reinforcements for the 10th Battalion in France where they fought at Ypres and Festubert in 1915. This accounts for the inclusion of those names in the 50th Battalion's Battle Honours.

The 50th again recruited to full strength and sailed from Halifax on 27 October 1915. On arrival in England it became part of 10 Brigade, 4th Canadian Division, CEF and arrived in France in August 1916. They took part in the battle of the Somme in October 1916, the attack on Vimy Ridge in April 1917 and the major battle at Passchendaele.

In 1918 after the German breakthrough, the Battalion held its positions on the Arras front, and in August the Battalion participated in the battle of Amiens and the subsequent breaking of the Drocourt-Queant Line. In September 1918, with another unit, the Battalion cleared the Bourlon Wood and in October 1918 it participated in the capture of Valenciennes.

Almost 5000 men served in the Battalion, and 900 were killed during the War. Among the many decorations was the Victoria Cross (VC) won by Pte J.G. Pattison. In present day Calgary there is a bridge spanning the Elbow River and a mountain in Jasper National Park named after this soldier.

The 14th Army Tank Regiment (The Calgary Regiment) was mobilized in February 1941. They left Calgary in March 1941 for Camp Borden to join the 1 Canadian Armoured Brigade, and arrived in Greenock, Scotland in July. They began training with Churchill tanks that September and in May 1942, the Regiment moved to the Isle of Wight with the 2nd Canadian Division to practice assault landings.

On 19 August 1942, the Regiment took part in Operation Jubilee, the Dieppe Raid. The Calgary Tanks went into history as the first tank regiment of the Canadian Army to engage in combat with the enemy. It was also the first occasion the “Churchill Tank” saw action.

The cost to the Regiment that fateful morning was high. Two officers and eleven men were killed, thirty-three men and officers wounded and taken prisoner along with 143 other men. Only five made it back to England out of the original contingent of 181 men who went ashore. Many of the POW's spent the rest of the war in captivity.

The unit returned to Seaford where they were reinforced and reorganized. In May 1943 the regiment was issued Sherman tanks and the following month they left for the Mediterranean to take part in the Invasion of Sicily with the 1st Canadian Division. In September 1943 they landed in Italy and began advancing up the Adriatic Coast. They crossed the Sangro River in November 1943 and captured Lanciano and in December they fought in the Battle of the Moro River.

The following spring they engaged in the Battle of the Gari River and the break through of the Gustav Lines leading to the fall of Rome on 5 June 1944. From August to December 1944 they engaged in the assault crossing of the Arno River and then advanced to the Gothic Line.