- Second World War (1939-1945)
- 1st Lieutenant (Lieutenant)
- Commanding Officer Company C, 70th Tank Battalion, attached 4th Infantry Division "Ivy", VII Corps, U.S. Army
For action performed on D-Day, June 6th, 1944 near Pouppeville/Manche département, Basse-Normandie, France. The tank unit of 1st Lieutenant John Ahearn was among the first to land on Utah Beach on 6th June 1944, D-Day. After moving inland, his tank was disabled by a mine. Attempting to rescue two wounded American paratroopers, he lost most of one leg and another foot to a mine.