As a Lieutenant in the Canadian Army Film and Photo Unit, he participated in the Normandy Landings, disembarking at Juno Beach on June 6, 1944, with the Highland Light Infantry of Canada.

Later he went on to photograph and record the liberation of France, Belgium and the Netherlands, and finally documented the occupation of Germany.

[3] When Canada joined the war against Nazi Germany in 1939, Bell was posted to Ottawa as a public relations photographer.

During the liberation of Dieppe in 1944, as the Manitoba Dragoons awaited orders to advance, members of the CFPU including Ken Bell and Brian O'Regan were the first Allied servicemen to enter the town.

[9] Bell's war photographs – taken with a Rolleiflex camera – are housed by the Library and Archives of Canada in Ottawa, Ontario.

[10] Many of the original negatives of his photographs are held by the Canadian Forces Photo Unit and the City of Toronto Archives.

In 1953 he published Curtain Call, a collection of photographs in which he "tried to show the changes brought by man and nature in the 5 years since VE day".