Twenty days after the start of the First World War, a training camp for troops was created in Valcartier, Quebec where the Bank opened a temporary office to help 33,000 troops (the first to go overseas) receive their pay. Back home, the Bank tackled the war’s enormous financial demands by promoting Victory Loans.

More than 2,800 Bank of Montreal employees served in both World Wars. In 1917, the Bank reported that 810 employees, almost half the bank's staff, had volunteered to fight. Spanning both wars, 314 bank employees lost their lives, 313 were wounded and 40 were taken prisoner of war. Many employees also served with great distinction, with 273 decorated for bravery.

Bank of Montreal supported the bravery of those who served in the First and Second World Wars, playing a quiet yet important role in Canada's war efforts.

During the First World War, the Bank recognized that while soldiers needed weapons and ammunitions, they also needed money. Twenty days after the start of the First World War, a training camp for troops was created in Valcartier, Quebec.

The Bank immediately opened a temporary office within this camp to help 33,000 troops receive their pay. Transactions took place under canvas tents. This was an invaluable service, because while Canadian troops were fighting overseas, their families still had to be provided for.

In London, England, BMO's Waterloo Place Branch became a home away from home for Canadian troops, holding more than 25,000 accounts of soldiers and officers by 1916. In addition to banking, mail from home could be picked up there, and the branch became a gathering place for Canadians.

Back home, the Bank tackled the war's enormous financial demands, successfully promoting Victory Loans through ambitious sales campaigns. Raising these essential funds allowed the Canadian government to finance its war effort without spiralling into foreign debt. As well, the Bank innovated by offering banking by mail to meet the needs of busy war industry workers.

Through initially regarded as one-time initiatives, these services were quickly repeated with the start of the Second World War. Also, Bank of Montreal President George Spinney was requested by the federal government to assist in developing the domestic war financing of the nation.

He was named Chairman of the Executive Committee of the National War Loan Committee in 1941 and organized the National War Finance Committee, laying down the campaign pattern for the nine Victory Loans to which Canadians subscribed so generously during the war years.

The Bank commemorated their courage and sacrifice in two books it published, The Great War 1914-1918 A Record of Service and Field of Honour. Both books are available at most public libraries and military museums across the country.

To further recognize their sacrifices, two statues were erected after the First World War and still stand at the Bank's main branches in Montreal and Winnipeg. The Winnipeg statue is a bronze sculpture modeled after Captain Wynn Bagnall, a Winnipeg Branch employee who received the Military Cross.

In 1951, Bank President B.C. Gardner unveiled a memorial in the Montreal Main Branch that lists the names of BMO employees who gave their lives in the Second World War, stating:

"It is well to remind ourselves that there are values in life more precious than those dealt with in the market place."