Joe Milner Sr. was born in Yorkshire, England and immigrated to Canada with his parents in 1910. He served with the 17th Cavalry Field Ambulance in Winnipeg, Manitoba before the war and attained the rank of Sergeant Major in April 1914. The same year Sergeant Major Milner was also awarded a Certificate of Military Instruction in Equitation.

The day before war was officially declared on Germany, Joe enlisted. According to the Calgary Herald at the time, he was the first man in the nation to join up.

With his militia experience, Joe was put in charge of recruiting for the 17th Cavalry Field Ambulance. He served overseas with the 56th Battalion, as a First Aid instructor.

After the war, Joe returned to Alberta and became one of the co-organizers of the first St. John Ambulance in Calgary. He worked in the Turner Valley oilfields during the 1920's and ran the first medical facility in the area which he expanded to provide emergency service to injured workers until they could be transported to hospital in Calgary. He also provided first aid instruction to hundreds of oil field workers.

During the Second World War, Joe was horrified by images of the London Blitz and re-enlisted, this time in the RCAF in the hopes of being sent overseas. However, he was kept in Canada and posted to various bases to assist in the ever expanding British Commonwealth Air Training Plan.

Tragically Flight Sergeant Joe Milner, along with five other RCAF members who were flying out of Whitehorse, Yukon, were killed on January 15, 1947 when their plane went down in Marsh Lake.