Major-General Keller was popular with his troops, who appreciated his manners and outspoken language; however, a drinking problem and several breaches of security measures before D-Day cost him the support of both his superior officers and his own staff. Ernest Côté, the quartermaster of the 3rd Division, called Keller a "conventional tactician" who was "very much a spit and polish officer who cut quite a figure in his battledress. We always cut a spare uniform for him, ironed and ready to go just in case. He cared for the division and was sensitive to any slight on its reputation. He was a very proud man and on top of the division's training."