A rugged-countenanced human male of middle years, Captain O'Shea commanded the freighter S.S. Huron in 2270. On stardate 6334.1, O'Shea agreed to transport a small consignment of the life-saving drug strobolin along with his standard commercial cargo of dilithium. Unfortunately, the strobolin, which was needed urgently aboard the U.S.S. Enterprise to save the life of the choriocytosis-stricken Commander Spock, was seized along with the Huron's dilithium cargo by a group of Orion pirates, who rendered Captain O'Shea unconscious in the process.