Seaman (E3) Gallegos served aboard the Destroyer-Mine Sweeper, USS Thompson (DMS-38). On 20 August 1952, his ship received shore battery fire from Songin, North Korea. The crew suffered 13 casualties.

Gallegos 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.