A graduate of Groton (class of 1915) and Harvard University (class of 1919) and the son of Professor J. Randall Coolidge of Boston, Massachusetts, Hamilton Coolidge was one of ten Harvard undergraduates accepted from a field of forty applicants for training at the Curtiss Flying School at Buffalo, New York in July 1916. A private with the United States Signal Corps, Aviation Section, stationed in Miami, Florida when the United States entered the war, Coolidge was sent the School of Military Aeronautics at the Massachusetts Institute of Technology on 5 June 1917. He embarked for France on 23 July 1917 and was commissioned 1st Lieutenant on 29 September 1917. After additional instruction at Issoudun he was assigned to the 94th Aero Squadron on 16 June 1918. He was promoted to Captain on 3 October 1918. On 27 October 1918 he was killed in action, his SPAD XIII taking a direct hit from an anti-aircraft shell near Chevières.
The Distinguished Service Cross is presented to Hamilton Coolidge, Captain (Air Service), U.S. Army, for extraordinary heroism in action near Grand Pre, France, October 27, 1918. Leading a protection patrol, Captain Coolidge went to the assistance of two observation planes which were being attacked by six German machines. Observing this maneuver, the enemy sent up a terrific barrage from anti-aircraft guns on the ground. Disregarding the extreme danger, he dived straight into the barrage, and his plane was struck and sent down in flames.
General Orders No. 37, W.D., 1919
French Croix de Guerre
Pilote de grand courage. A abattu en flammes, le 7 juillet 1918, un biplane ennemi dans la région de Grisolles.