Returning to Canada, he embarked on an academic career, teaching English at the University of New Brunswick, before being appointed president of Union College in Schenectady, New York.

Having served with the King Edward's Light Horse while at Oxford University, followed by a year with the 28th New Brunswick Dragoons before filling the position of junior major with the 85th Overseas Battalion.

[3] where he played a crucial role in recruiting and training of the 185th Canadian Infantry Battalion (Cape Breton Highlanders), CEF.

Details of the 94th Victoria Regiment "Argyll Highlanders" were called out on active service on 6 August 1914 for local protection duties.

The 85th Battalion (Nova Scotia Highlanders), CEF was authorized on 10 July 1915 and embarked for Great Britain on 12 October 1916.

The 185th Canadian Infantry Battalion (Cape Breton Highlanders), CEF[4] was authorized on 15 July 1916 with Day as its lieutenant colonel, and embarked for Great Britain on 12 October 1916.