He fought with extreme gallantry to defend the outpost which had been established near Dingalan Bay. Just before daybreak approximately 100 Japanese stealthily attacked the perimeter defense, concentrating on a light machinegun position manned by 3 Americans. Having completed a long tour of duty at this gun, Pvt. McKinney was resting a few paces away when an enemy soldier dealt him a glancing blow on the head with a saber. Although dazed by the stroke, he seized his rifle, bludgeoned his attacker, and then shot another assailant who was charging him. Meanwhile, 1 of his comrades at the machinegun had been wounded and his other companion withdrew carrying the injured man to safety. Alone, Pvt. McKinney was confronted by 10 infantrymen who had captured the machinegun with the evident intent of reversing it to fire into the perimeter. Leaping into the emplacement, he shot 7 of them at pointblank range and killed 3 more with his rifle butt. In the melee the machinegun was rendered inoperative, leaving him only his rifle with which to meet the advancing Japanese, who hurled grenades and directed knee mortar shells into the perimeter. He warily changed position, secured more ammunition, and reloading repeatedly, cut down waves of the fanatical enemy with devastating fire or clubbed them to death in hand-to-hand combat. When assistance arrived, he had thwarted the assault and was in complete control of the area. Thirty-eight dead Japanese around the machinegun and 2 more at the side of a mortar 45 yards distant was the amazing toll he had exacted single-handedly. By his indomitable spirit, extraordinary fighting ability, and unwavering courage in the face of tremendous odds, Pvt. McKinney saved his company from possible annihilation and set an example of unsurpassed intrepidity.

John McKinney enlisted in the Army at Fort McPherson on November 23, 1942 as a private at age 23.