At the time of his Medal of Honor action, Truesdale was simultaneously a lieutenant in the Nicaraguan native army.

Despite losing his right forearm, he continued to serve with the Marine Corps until his retirement as a chief warrant officer in May 1946.

[1] The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Corporal Donald L. Truesdale, USMC, for service in Nicaragua as set forth in the following: Citation: For extraordinary heroism in the line of his profession above and beyond the call of duty at the risk of his life, as second in command of a Guardia Nacional Patrol on 24 April 1932, engaged, at the time, in active operations in the field against armed bandit forces in the vicinity of Constancia, near Coco River, Department of Jinotega, Northern Nicaragua.

Corporal Truesdale, who was several yards away at the time, could easily have sought cover and safety for himself but instead, knowing full well the grenade would explode within two or three seconds, and with utter disregard for his own personal safety, and at the risk of his own life, rushed for the grenade, grasped it in his right hand and attempted to throw it away from the patrol before it exploded.

Corporal Truesdale, by his actions, took the full shock of the explosion of the grenade upon himself, thereby saving the lives of, or serious injury to, his comrades in arms.