Ernest Wrentmore was born on November 9, 1904, in Auburn, Ohio. By lying about his age, he was able to enlist under the name Henry E. Monroe in the U.S. Army for service in World War I on September 28, 1917, at age 12, making him the youngest American, and possibly the youngest person in the world, to serve in World War I. Pvt Wrentmore was assigned as a Bugler and Runner with Company I, 60th Infantry Regiment of the 5th Division, and deployed with the unit to France in April 1918. He participated with his unit in the St. Mihiel, the first American Offensive, Alsace and Lorraine, and the Meuse-Argonne offensives, and he was wounded and gassed several times. After remaining in Europe on Occupation Duty, he returned to the United States in early February 1919, and received an honorable discharge from the Army on February 18, 1919. He again enlisted in the U.S. Army on February 11, 1929, and served as a Clerk with the 30th Infantry Regiment at the Presidio of San Francisco, California, until receiving an honorable discharge on January 13, 1930. Wrentmore was accepted for Flying Training as a Flying Cadet and went on active duty on June 25, 1931, at March Field, California, but he failed flight training and was honorably discharged on August 20, 1931. Wrentmore was given a direct commission as a 1st Lieutenant in the U.S. Army Air Forces on September 15, 1942, and he went on active duty to attend Officer Training School on September 28, 1942. He completed Officer Training School at Miami Beach, Florida, in October 1942, and then attended the Combat Intelligence Officer course at Harrisburg, Pennsylvania, from November to December 1942. His next assignment was as an Intelligence Officer with the 416th Bomb Squadron of the 99th Bomb Group at Sioux City Army Air Base, Iowa, from December 1942 to February 1943, and then deployed to North Africa from March to September 1943. He then returned to the United States and took leave, followed by service as an Intelligence Officer with Headquarters IV Bomber Command at San Francisco, California, from February to September 1944. During this time Capt Wrentmore attended the Air Staff Course at Command and General Staff School at Fort Leavenworth, Kansas, from June to August 1944. His final active duty assignment was with 2nd Air Force at Lincoln Army Air Field, Nebraska, from October 1944 until he left active duty and joined the Air Force Reserve on November 4, 1944. Lt Col Wrentmore served with Air Force Reserve units in Los Angeles, San Rafael, San Anselmo, and Santa Barbara, California, before retiring on November 30, 1964. He died at the U.S. Air Force Hospital at Beale AFB, California, on December 11, 1983, and was buried at Arlington National Cemetery. For his heroism during World War I, he was recommended for the Medal of Honor and the Distinguished Service Cross, but neither of these medals were ever awarded.