Davis was a Human Starfleet officer assigned to the engineering department of the USS Enterprise in the 2260s. In 2267, Davis and a security guard accompanied Captain James T. Kirk and Commander Spock to the planet Gateway to locate Dr. Leonard McCoy. (TOS novelization: The City on the Edge of Forever) When the Enterprise became ensnared in the gravity well of Questar M-17 in 2269, Lt. Commander Scott ordered Davis and Gardner to put all power into reversing the engines. (TAS - Log One novelization: Beyond the Farthest Star)