Boon received the country's highest award for bravery during combat, the Medal of Honor, for his action during the Battle of Sailor's Creek in Virginia on 6 April 1865.

His company was on the right flank of the Cavalry charge commanded by General George A. Custer's 3rd Brigade against the center of the Confederate defenses.

On the 10th of May, 1864 during the battle of Wytheville Virginia, Boon was seriously injured, a bullet piercing through his neck in close proximity to his spinal cord, an injury which troubled him throughout the rest of his life.

He was present with his unit at the surrender of the Confederate Army under General Robert E. Lee at Appomatox Virginia only 3 days after the battle of Saylers Creek.

After the war Boon returned to the grocery business for a while but soon left to go into farming, a trade in which his family was involved while growing up.