John D. Oehlberg was born on January 10, 1922, in Cook County, Illinois. He had three years of high school, had an occupation in shipping and a receiving clerk, and was single without dependents upon enlistment.

John entered military service in Chicago, Illinois, on September 25, 1942. He served in Company D, 2nd Ranger Battalion, as a Private First Class during World War II. He was Missing in Action on June 6, 1944, at the age of 22, at Pointe du Hoc, during the American assault on Omaha and Utah beaches in France. PFC Oehlberg is memorialized on the Tablets of the Missing, Normandy American Cemetery, Colleville-Sur-Mer, France.