The unit's active participation in World War 1 came with the involvement of the 12 and 13 Regiments of the Canadian Mounted Rifles Canadian Expedition Force (CEF) which were direct descendants of the 15th Light Horse and the 31st, 113th, 175th and the 187th Overseas Battalions CEF which were created with the advent of the war.

Despite its cavalry beginnings, the Regiment fought in the war as infantry and arrived back in Canada at the war’s end with 19 Battle Honours to its credit, including such notable actions as Vimy and Ypres. After the War, the Vimy Memorial was unveiled by King Edward VIII. During his speech he speaks to the great sacrifice the nation made and the accomplishments of the men who won the war for the Empire.

The period between wars saw the re-emergence of the 15th Light Horse, henceforth called the 15 Alberta Light Horse and the Alberta Regiment, the former unit being cavalry out of Calgary and the latter being infantry out of Medicine Hat.

Of particular note, the 31st Bn CEF participated in the first tank attack in history at the battle of Coucelette on 15 Sept 1916 while the 19th Dragoons (at that time known as A Sqn, Cdn Light Horse) made one of the last cavalry charges in Canadian history at the battle of Iwuy on 10 October 1918.

This means that among the predecessor units of the SALH, one participated in the first military operation involving the tank in September 1916 and another which mounted the last cavalry charge in Canadian history in 1918.