Lieutenant Evans 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 a historic five-year mission that starship undertook. He served as one of the ship's security officers in 2268.
That same year, Evans reported a disturbance in crew quarters to Kirk, and discovered that Troyian Ambassador Petri had been stabbed by the Elasian Dohlman, Elaan.
Evans later found Kryton conducting sabotage in the engineering room of the Enterprise. Kryton attacked Evans and stole his phaser, which he used to kill himself. (TOS: "Elaan of Troyius")