Ensign Rollins was a Starfleet officer who served as tactical officer on board the USS Voyager under the command of Captain Kathryn Janeway in 2371. He manned the tactical post as an Ensign when the starship departed from Deep Space 9 before Lt. Tuvok came aboard.
After Voyager was swept into the Delta Quadrant, Rollins was left in charge of the bridge, and later served as temporary flight controller, until Lt. jg Tom Paris was given the position. (VOY: "Caretaker") Rollins was promoted to the rank of Lieutenant, serving as Paris' immediate superior officer, following the restructuring of Voyager's chain of command.
In mid-2372, Rollins was unhappy with Paris' poorly punctuated conn reports, noting that they were not according to Starfleet protocol. Their clash turned physically violent, apparently because Paris did not like his attitude. (VOY: "Dreadnought") This incident was part of a ploy by Janeway and Paris to draw out a mole transmitting information to the Kazon-Nistrim. (VOY: "Investigations")