John Kelly was born on June 24, 1898, in Chicago, Illinois. He enlisted in the U.S. Marine Corps on May 15, 1917, and completed basic training at Parris Island, South Carolina, in July 1917. Pvt Kelly joined the 78th Company, 6th Marine Regiment at Quantico, Virginia, in September 1917, and he embarked with his Regiment from Philadelphia, Pennsylvania, aboard the transport USS Henderson (AP-1) in January 1918. He arrived in France in February 1918, and participated in combat at Château-Thierry, Saint-Mihiel, Blanc Mont Ridge, and the Meuse–Argonne offensive, as well as the march to the Rhine River. For his heroism at the Battle of Blanc Mont Ridge, Pvt Kelly would be awarded both the Army and Navy Medal of Honor. He remained on Occupation Duty in Germany after the war ended, and recieved an Honorable Discharge from the Marine Corps at the Marine Barracks, Quantico, Virginia, on August 14, 1919. John Kelly died on November 20, 1957, and was buried at All Saints Cemetery in Des Plaines, Illinois.

His Navy Medal of Honor Citation reads:

For conspicuous gallantry and intrepidity above and beyond the call of duty in action with the enemy at BLANC MONT RIDGE, France, October 3, 1918. Private Kelly ran through our own barrage one hundred yards in advance of the front line and attacked an enemy machine-gun nest, killing the gunner with a grenade, shooting another member of the crew with his pistol and returned through the barrage with eight prisoners.

His Army Medal of Honor Citation reads:

Private Kelly ran through our own barrage 100 yards in advance of the front line and attacked an enemy machinegun nest, killing the gunner with a grenade, shooting another member of the crew with his pistol, and returning through the barrage with eight prisoners.