Corporal Grimsley was a member of Headquarters Company, 1st Battalion, 38th Infantry Regiment, 2nd Infantry Division. He was listed as Missing in Action while fighting the enemy in South Korea on 12 February 1951. He was presumed dead on 5 March 1954. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Grimsley was awarded the Purple Heart, the Combat Infantryman Badge, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.