First Lieutenant Cumming was appointed again a platoon leader in 51st Company on June 1, 1918, and subsequently led his unit to the Battle of Belleau Wood. During the fighting near the town of Château-Thierry, Cumming led his platoon to the attack and was hit by enemy machine gun fire to his right leg on June 11. His whole platoon was wiped out except himself and another soldier. Cumming later described his engagement as follows: