While both Canada and United Sates militaries participated in sports before and after WWI, their participation in hockey did not emerge until recruitment impacted the amateur hockey world.

When the war started in August 1914, the Canadian military needed to modernize overnight, including raising a force. In 1914, Canada was in recession and unemployment was high. Additionally, patriotism surged amongst the general populace. As a result, there was a large willing and available manpower pool to resource units.

While notable hockey players trickled into CEF units between August, 1914 and August, 1915, a shocker came when the entire Selkirk hockey joined the 61st Battalion in September, 1915. However, this wasn’t reason why the CEF jumped into amateur hockey. It was the reason why it took off.

Richard Holt lays out how the CEF built units. In general, once a unit was authorized (or sponsored in the case of the Princess Patricia’s Canadian Light Infantry), recruiting would happen locally. The unit would also stay in garrison until initial training was complete, which was usually four months. Sports provided an outlet for those waiting for their unit to reach full strength. So, it wasn’t that the 61st waited  for hockey; hockey forced itself on to the 61st.

With the Selkirk team on hand, the 61st had a strong team and the Winnipeg leagues were voted to be playing for the Allan Cup. In the teens and twenties, the Allan Cup was possibly more popular than the Stanley Cup. One reason was that amateur hockey was more popular than professional hockey. And, The Allan Cup was for Amateurs only. As soon as newspapers reported on the 61st Battalion’s entrance to amateur hockey, other units submitted their application, including the Lord Strathcona’s Horse (Royal Canadians), the 40th Battery (Conn Smythe’s unit), the 94th Battalion (Thunder Bay) and many others. At least 24 CEF units participated in various amateur hockey leagues for the 1915-1916 season. (Note: a table of units is below.)

The 61st Battalion won the Allan Cup and defended the title throughout the 1916 season. In April, the 61st Battalion was declared the champions and shipped off to war. In addition to the 61st Battalion in the senior league, the 61st’s intermediate team won their league’s championship and the Lord Strathcona’s Horse (Royal Canadian) won the Winnipeg Central Hockey Associations’ championship title. These successes on the ice led to increased CEF participation in hockey, which led to the creation of the Military Hockey League for 1916-1917.

Nearly every CEF unit participated in the 1916-1917 season. Most (in)famously, the 228th under the McNamara brothers attempted to repeat the 61st’s success, except in the N.H.A. However, scandals and a strict adherence to deployment schedules interrupted the 228th’s chance. By 1918, the United States military supported hockey teams. Thomas “Tom” Howard Jr and John “Jack” Howard played for several U.S. Navy teams.

With the popularity of hockey in the late-teens, a lingering question remains on if the military recruited hockey players for hockey (promote support or recruitment) or war. The 228th supposedly offered Eddie Oatman $1200 to play hockey, but was unceremoniously dismissed two days prior to the 228th leaving for the front. Oatman claimed to have never been enlisted or properly enlisted. In contrast, the Howard brothers joined the Naval Reserve in 1917. Tom Jr. was passed from Newport Naval Yard to Charleston Naval Yard solely for hockey. In regards to the CEF, J.J. Wilson suggests that the CEF targeted hockey players for recruitment. While Wilson’s reasons may be contentious, it is clear the CEF appealed to hockey players to join. Captain  James Sutherland wrote an open letter and closed with the words “The whistle has sounded. Let every man play ‘the greatest game of his life’.”

Fri, Dec 31, 1915 – 12 · The Gazette (Montreal, Quebec, Canada) · Newspapers.com

Here is an incomplete table of CEF units that had hockey teams who participated in the various amateur leagues. This chart contains units with hockey teams who participated in Amateur hockey leagues as noted in newspapers from October 1915 to March 1916. It is likely that some units were missed, like 70th Regiment (London). Also, some units only competed in exhibition games, like 101st Battalion (Winnipeg Light Infantry). (NOTE: Blanks indicate unknown information; question marks are unconfirmed.)

Season	Unit	Location	League	Cup Winner	Reference
1915-1916	61st Battalion	Camp Sewell/Hughes	Winnipeg Patriotic League	1916 Allan Cup	https://www.newspapers.com/image/64791888/
1915-1916	Strathconas Horse		Central Hockey Association	Yes	https://www.newspapers.com/image/44176361/
1915-1916	101st Battalion	Fort Garry Horse	exhibition		https://www.newspapers.com/image/44180414/
1915-1916	128th Battalion		Saskatchewan		https://www.newspapers.com/image/61685595
1915-1916	184th Battalion				https://www.newspapers.com/image/44180414/
1915-1916	184th Battalion				https://www.newspapers.com/image/44182387/
1915-1916	222nd Battalion (Carman Detachment)				https://www.newspapers.com/image/44183227
1915-1916	32nd Battery (St. Patricks)		Kingston City League		https://www.newspapers.com/image/41515094/
1915-1916	33rd Battery	Camp Barriefield	Ontario Hockey Association Senior		https://www.newspapers.com/image/61685870/
1915-1916	34th battery (?)				https://www.newspapers.com/image/44182501/
1915-1916	40th Battery (aka Sportsmen’s Battery)		Ontario Hockey Association Senior		https://www.newspapers.com/image/44178093/
1915-1916	45th Battalion		Winnipeg		https://www.newspapers.com/image/44176666/
1915-1916	53rd Battalion		Central Hockey Association		https://www.newspapers.com/image/44183611/
1915-1916	59th Battalion (?)				https://www.newspapers.com/image/41515315/
1915-1916	62nd Battalion				https://www.newspapers.com/image/61686398/
1915-1916	68th battalion		Saskatchewan union		https://www.newspapers.com/image/419642305/
1915-1916	76th Battalion		Ontario Hockey Association Intermediate		https://www.newspapers.com/image/61685577
1915-1916	77th Battalion	Camp Rockcliffe	City League		https://www.newspapers.com/image/41515534/
1915-1916	78th battalion		Thuner Bay League		https://www.newspapers.com/image/44173146/
1915-1916	79th Battalion				https://www.newspapers.com/image/44180414/
1915-1916	84th Battalion		Ontario Hockey Association Intermediate		https://www.newspapers.com/image/44178093/
1915-1916	93rd Battalion	Camp Barriefield	Ontario Hockey Association Intermediate		https://www.newspapers.com/image/61685789/
1915-1916	94th Battalion	Fort William	Thuner Bay League		https://www.newspapers.com/image/44176932/
1915-1916	B Squadron, Depot Regt, C.M.R.		Ontario Hockey Association		https://www.newspapers.com/image/44183620/

Sources:
1. Holt, Richard (2017) “Filling the Ranks: Manpower in the Canadian Expeditionary Force, 1914-1918”, McGill-Queen’s University Press
2. Selkirk Hockey Team Joins 61st Battalion: Thursday, 2 September 1915, The Winnipeg Tribune (Winnipeg, Manitoba, Canada) https://www.newspapers.com/image/44173858/ – newspapers.com
3. Strathcona’s Horse Wins Central Hockey Championship: Saturday, 11 March, 1916, The Winnipeg Tribune (Winnipeg, Manitoba, Canada) https://www.newspapers.com/image/44176361/ – newspapers.com
4. Military Hockey Leagues Joins Manitoba Body: Thursday, 11 January 1917, The Winnipeg Tribune (Winnipeg, Manitoba, Canada) https://www.newspapers.com/image/44191459/ – newspapers.com
5. Hockey Club in trouble due to players in service: Saturday, 27 October 1917 The Gazette (Montreal, Canada) https://www.newspapers.com/image/419798192/ – newspapers.com
6. JJ Wilson (2007) Skating to Armageddon: Canada, Hockey and the First World War, The International Journal of the History of Sport, 22:3, 315-343, DOI: 10.1080/09523360500048746

Additional Sources:
1. March 2017 Canadian Armed Forces Men’s Hockey Championship: https://www.facebook.com/events/1725973017676704/
2. U.S. Army vs CAF hockey match, Dec 2017:  https://www.army.mil/article/198453/all_army_ice_hockey_team_earns_hard_fought_4_2_win_over_canadian_armed_forces_team