Pastores served as a stores ship, responsible for delivering supplies to military personnel in combat and non-combat areas.

Pastores was one of the merchant ships chartered by the Navy during World War I to transport U.S. forces to Europe, through submarine-infested waters.

She decommissioned and was returned to the United Fruit Company on 8 October 1919 and served on the West Indies–Central American run until 20 December 1941, when acquired by War Shipping Administration, from whom the Navy again chartered her.

Pastores supplied forces on Trinidad, Cuba, Bermuda, and other Caribbean islands with fresh food and returned to the United States with full cargoes of sugar.

Operating from San Francisco, California, and Pearl Harbor in 1944, the ship discharged her chilled and frozen cargo to the fighting fleet and shore bases in the Ellice, Gilbert, Marshall, and New Hebrides Islands.

The first reefer ship at Leyte Gulf after the invasion, she arrived before receiving facilities were ready on the beach and thus dodged Japanese aircraft until able to unload.