Lieutenant Pitcairn was a male Human Starfleet officer in the 23rd century. He served in the operations division aboard the USS Enterprise under the command of Captain James T. Kirk, during the historic five-year mission. He served as the ship's security chief in 2267.
That year, Pitcairn accompanied Vinci to the bridge, when Doctor Leonard McCoy ordered Spock to be put under arrest. Later, he stood next to the injured Fleet Captain Christopher Pike during Spock's court martial. (TOS: "The Menagerie, Part I", "The Menagerie, Part II")