Sévigny served in the Canadian Army during World War II, and lost a leg in the Battle of the Rhineland. He was awarded the Virtuti Militari, Poland's highest military decoration, for his involvement in the battle at Hill 262. Along with his Polish comrades of the 1st Polish Armoured Division, he denied access to Panzer divisions trying to break out of the Falaise pocket in August 1944. The action resulted in the encirclement and capture of 50,000 German troops. He also received France's Croix de Guerre and Belgium's Croix de Guerre. After the war he wrote a book "Face à l’ennemi" about his experiences. It won the Prix Ferrières de l’Académie française in 1948. In 1965, he wrote his second book, "This Game of Politics" (McClelland and Stewart).