Captain Dorrien was a veteran of World War II, serving in the European and Middle Eastern Theaters of Operation. In Korea, he served with the 5th Regimental Combat Team and, after the Armistice, as an advisor with that United Nations Korean Advisory Group. He died of other causes at Chosan-ri, Korea on 29 August 1953.

Dorrien was awarded the Purple Heart, the Combat Infantryman's 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. He was also awarded the Croix de Guerre, the Presidential Unit Citation, the European Theater of Operations Medal and the World War II Victory Medal for his service during World War II.