Neelix first appeared in Star Trek: Voyager in the pilot episode, "Caretaker", joining the crew of the USS Voyager, in which he is rescued from the violent Kazon race on an arid planet. Rescued with him is his partner, Kes a member of a different race living on the same planet, the Ocampa. Previously a space trader, following his rescue by the Voyager crew, Neelix offers his services as a guide to the Delta Quadrant and appoints himself "Chief Morale Officer", also taking over the mess hall and becoming the ship's cook.
The captain of the ship, Kathryn Janeway, simply tolerates the character at first, but later comes to respect and value Neelix as an important member of the crew. She eventually appoints him as unofficial ship's Ambassador.
The character's relationship with Kes is later terminated by her, during a conflict that occurs on an away mission. The two characters are shown to remain good friends thereafter. During the course of the series, Neelix develops a friendship with another character, Tuvok, the ship's security chief.
Neelix exits the show in the final season episode "Homestead", choosing to join an asteroid-based colony of exiled Talaxians, and returns for a cameo in the series finale, "Endgame".