The Canadian Bank of Commerce saw 1,701 of its employees enlist in the Great War while 518 employees from the smaller Imperial Bank of Canada answered the call. They won numerous honours including the Victoria Cross, and 321 made the ultimate sacrifice.

The Commerce branch in London, England experienced the war first-hand. While the branch readied itself for hostilities, the employees carried on with the day-to-day operations of the branch, even in the most trying circumstances. At home, in Canada, the banks faced different challenges.

With so many bank officers entering military service, the banks experienced a staff shortage. By May 1916 1,050 male employees from The Canadian Bank of Commerce had enlisted and the bank turned to women to fill these empty jobs. At the end of the war, 500 women were working for the Imperial and 1,446 for The Commerce.

In 1920, the President of The Commerce acknowledged the significant role women had played during the war. "Right nobly did they buckle to their tasks, and through their devoted labours our young men were freed for active service, and the business of a nation at war went on."

The Canadian Bank of Commerce went to great lengths to commemorate its staff that had served in the war. Memorials were commissioned for branches as well as Head Office. In addition, a two-volume book was published, Letters From the Front, which included staff profiles and accounts of their war experiences.