Lieutenant Mallory 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, as one of the ship's security officers.
In 2267, Mallory was one of four security officers that made up the landing party of nine that surveyed the surface of Gamma Trianguli VI. Following the death of Hendorff, Kirk ordered Mallory and Marple to make a full reconnaissance of the village near their location, careful to avoid contact with the humanoid natives.
His observations of the village, which he attempted to communicate via his communicator to Kirk, were that it was "primitive, strictly tribal from the looks of it," however, mid-sentence in describing what would later be determined to be Vaal, interference interrupted the message. Mallory ran to inform his superiors his findings, calling out where to go, but in his excitement, and unaware that Spock had discovered volatile explosives in the ground strata, he carelessly stepped on one of the rocks, dying from the blast; the third of four security guards to die that day.