Lt. Ker enlisted with the 48th Highlanders just after war was declared in September 1939 and was one of 52 Officers in the 2nd Battalion, 48th Highlanders of Canada. While training in Camp Borden, Ontario Lt Ker was wounded by a mortar round that had misfired. His wounds prevented him from completing training and going overseas to the 1st Battalion, 48th Highlanders. He remained a proud Highlander for the rest of his life.

In 19, Lt Ker, a member of the Southam family, led the fundraising and commission of an oil portrait of his relative, Brigadier W. W. Southam, DSO, ED who had commanded the 1st Battalion in England and after promotion to Brigadier in the 2nd Canadian Division was captured on the beaches at Dieppe in 1942.