"Callard has an illustrious army career thanks to his bravery, common sense and the knowledge that sometimes the thing you can say is nothing."
— Call of Duty 3 bonus materials section.
Sgt. Callard was part of The Argyll and Sutherland Highlanders of Canada and the member of the platoon led by Lt. Jean-Guy Robiechauld. He first helped to take an important industrial area and then defend it from German reinforcements. Afterwards, he helped take the Laison river. Finally, he and his squad moved through a town clearing it of German soldiers and rescuing a friendly tank crew, and taking shelter when a King Tiger tank had Lt. Robiechauld's squad pinned down. He and his squad went down to plant a satchel charge on a German oil dump that was going below the tank (underground), but the charge did not go off. Realizing that a defective charge could kill the entire platoon, he sacrificed himself and manually detonated the charge. His actions allowed the Canadians to take the small village, and push reinforcements through to the Polish who were fighting a battle on top of Mount Ormel. Lt. Robiechauld stated that Callard will be put in for the Victoria Cross, which is the British Empire's most honorable and highest military decoration.
After Callard's death, the player can see Lt. Robiechauld wipe his eyes when he says "We thought we had lost you like... we lost Callard. I'm putting him in for the Victoria Cross you know, and you for a promotion, Corporal." This states that he might have been emotionally moved after Callard's death.