Montgomery was a male Human Starfleet officer who lived during the mid-23rd century. He served in the operations division aboard the USS Enterprise under Captain James T. Kirk, during his historic five-year mission, as one of the ship's security officers in 2267.
Montgomery was later assigned by Spock to escort Commodore Matthew Decker to Sickbay. En route, Decker attacked and overpowered Montgomery, in one of the corridors outside the turbolift, and afterward dragged Montgomery's unconscious body into an adjacent room. (TOS: "The Doomsday Machine")