After his studies in high school he worked briefly at Fleet Aerospace before joining in 1942 on his 18th birthday the Royal Canadian Air Force (RCAF). In Europe in 1943/44 as a reconnaissance pilot flying North American Mustang fighters he completed a 135 mission tour of operations at the end of November 1944 in Holland. On 17 July 1944, he had spotted a fast moving staff car, usually used to carry German officers. According to Rohmer, the German officer being carried was Field Marshal Erwin Rommel. Rohmer reported the car's location to Group Control Centre, which sent in a Spitfire piloted by Canadian Charley Fox. Rohmer took part in D-Day and the Battles of Normandy, Belgium and Holland. He is now the senior surviving Canadian veteran of all of those Battles.