O'Donnell was a Human male Starfleet officer who served aboard USS Voyager under Captain Kathryn Janeway during the 2370s.
A hologram of O'Donnell helped Chakotay take the ship in Tuvok's holodeck program entitled Insurrection Alpha. In the scenario, he was one of twenty-five Starfleet crewmembers who sympathized with the Maquis in supporting Chakotay's takeover of the ship. In the original scenario he and Carlson delivered a duty roster to the bridge when initiated the insurrection. During the scuffle, he took out Ensign Harry Kim. He and Carlson later escorted the prisoners who refused to join under Chakotay's leadership to the brig, where he remained to guard the imprisoned bridge crew.
O'Donnell later appeared in Seska's variation of the program, when he assisted Chakotay in capturing Tuvok and Tom Paris. (VOY: "Worst Case Scenario")
O'Donnell was part of the security team along with another security officer which escorted Captain Janeway and Seven of Nine aboard the USS Dauntless to face Arturis and his false claims. When Arturis turned around to active the quantum slipstream drive of his ship, they tried to stop him but were knocked to the ground by Arturis. He was then among the Voyager crewmembers who were successfully beamed back aboard Voyager. (VOY: "Hope and Fear")