An underground Megaloboxer from the outskirts of town whose real name is unknown, Junk Dog is forced to throw fights to earn money for his crooked manager, Gansaku Nanbu. He had something that most boxers lack however: ''A True Fighting Spirit''. He fights not just for the sake of earning a dime or two, but to prove himself as a Megaloboxer. So, he gets challenged by Yuri to join the Megalonia Tournament and fight him in order to prove he's a real fighter, he immediately jumps at the opportunity and goes for it, taking on the name "Joe" when he has a Citizen ID forged in order to enter the Megalonia tournament.
He initially fights with old Gear that is constantly in need of repair. He later takes on the ring name "Gearless Joe" as part of a gimmick to rise in the rankings quickly, fighting without Gear against Gear-equipped opponents. Joe also later met and saved a orphan boy named Sachio and his friends, together along with Nanbu they formed "Team Nowhere".
(His counterpart in the original Ashita no Joe is Joe Yabuki.)
