Ensign Murphy was a Starfleet science division officer serving aboard the USS Voyager under Captain Kathryn Janeway. Murphy was stranded in the Delta Quadrant when Voyager was forcibly brought there by the Caretaker in 2371.
That year, B'Elanna Torres and Seska discussed how Murphy had once dated one of the Delaney twins (Megan and Jenny) before Tom Paris and Harry Kim "made their move", after he passed both in the mess hall. (VOY: "Prime Factors")
He also visited the mess hall when Chakotay and Kenneth Dalby had a dispute, ending on the ground for Dalby, and later when the Maquis crewmembers had their run through the mess hall. (VOY: "Learning Curve")
Murphy was in the mess hall when a few crewmembers chatted with the 37's and was talking with a fellow crewmember himself. (VOY: "The 37's")
He visited the mess hall when Kes discovered a spawn beetle in salad she brought from the airponics bay. (VOY: "Elogium")
Murphy attended the memorial service for fellow crewman Kurt Bendera in 2372. (VOY: "Alliances")
He was among the crewmembers in the mess hall who were surprised by Quinn's appearance. (VOY: "Death Wish")
In 2372, he joined a fellow crewmember in the mess hall and was irritated when Chakotay and Paris had a dispute. (VOY: "Lifesigns")
He passed Neelix and Harry Kim in a corridor on their way to the next turbolift. (VOY: "Investigations")
Murphy visited the mess hall again shortly after the transporter accident which created Tuvix. (VOY: "Tuvix")
Murphy was in the mess hall when the captain says goodbye to the crew. Also was on the bridge when Tuvok decides to seek help from the Vidiian. (VOY: "Resolutions")
He was a member of the group together with Michael Parsons, and the rest of all crew, when they were abandoned on Hanon IV. (VOY: "Basics, Part I", "Basics, Part II")
In 2373, he passed Chakotay and Tuvok on their way to main engineering while the Voyager explored the Azure Nebula. (VOY: "Flashback")
Murphy attended the banquet for the Enarans held in the mess hall aboard Voyager and witnessed B'Elanna Torres' accusations against the crimes of the Enarans. (VOY: "Remember")
He was one of the crewmembers who transported equipment through a corridor when the crew prepared to enter Borg space. (VOY: "Scorpion")
Ensign Murphy was played by regular background actor Brian Donofrio who received no credit for his appearances.