Hospital Corpsman Third Class Trimm served with Headquarters and Service Company, 3rd Battalion, 1st Marines, 1st Marine Division. He was seriously Wounded in Action while tending his wounded comrades on 28 November 1950 and died on 20 December 1950. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Trimm was awarded the Purple Heart, the Combat Action Ribbon, 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.