McNulty's most significant act of valor occurred in action between Blanc Mont and St. Etienne, France, on October 4, 1918, while he was a gunnery sergeant. With the crew of his machine gun all killed or wounded about him and while himself under heavy artillery and machine gun fire and severely, near mortally, wounded, Gunnery McNulty voluntarily stood his
Vickers gun against
Central Powers forces until they were repulsed. Not relinquishing his post even after the enemy retired, McNulty had to be then actually ordered off the field and to the rear for surgical treatment by his commanding officer. ==Rise through the ranks to commissioned officer==