Joleg was a Benkaran prisoner aboard a Nygean prison ship in 2377, due to be executed for murder. He and the others aboard were rescued from the destruction of their ship by the Federation starship USS Voyager.
While incarcerated in Voyager's cargo bay, Joleg struck up a friendly exchange with Neelix, informing him that he was a victim of circumstance and the prejudice in the Nygean justice system against Benkarans. As a result, Neelix promised to help Joleg make an appeal for clemency to the victim's family, and to convey a letter to his brother.
However, Joleg's letter allowed his brother to locate Voyager and attempt to free him. During the attack, Joleg took the Nygean warden Yediq hostage, but was stopped from killing him by Iko. Neelix was outraged by his betrayal of their trust, but Joleg maintained he had no idea of his brother's intentions and that he might be sick, just like Iko, but Neelix refused to trust him anymore. (VOY: "Repentance")