Bandit Keith was the American champion, but lost a duel to Pegasus J. Crawford, who read his mind, and has been seeking revenge on him since then for humiliating him. He and his henchmen, Ghost Kotsuzuka, Satake, and Takaido entered Pegasus' tournament Duelist Kingdom, and took Katsuya Jonouchi into a duel arena in a cave, where Kotsuzuka dueled Jonouchi while Keith was giving him instructions. Jonouchi won, so Keith beat up Kotsuzuka, Takaido, and Satake, stealing their Star Chips so that he had ten Star Chips and could enter Pegasus' castle for the finals.
In the semifinals, Keith dueled Jonouchi, whom he picked on almost as bad as Seto Kaiba did, but he did not have either of the two entry cards, so he stole Jonouchi's card. He was shocked when Jonouchi turned up with a card (given to him by Mai Kujaku, who had lost the previous duel to Yugi), and cheated during his duel with Jonouchi by keeping cards to power up his Slot Machine AM-7 beneath his wristband, but in spite of this, Jonouchi won. He tried to disqualify Jonouchi by saying that the card was not his, but his knowledge of this revealed that he stole Jonouchi's card, and Pegasus pointed out his cheating in the duel, and ordered Keith taken away. Keith broke free, drew a pistol (removed in the 4Kids dub), and demanded that Pegasus give him the location of the prize money. Pegasus was not fazed and hit a switch that opened a trap door, ejecting Keith from the island.
Bandit Keith was later found by Marik Ishtar and his Rare Hunters, and Marik controlled him using his Millennium Rod. While posing as a fortuneteller, the possessed Keith took Yugi's Millennium Puzzle and dueled Yugi over it. He was released from Marik's control by Yami Bakura, and as Marik attempted to regain control, Keith attempted to fight him off, causing a fire in the warehouse in which they were dueling. Keith escaped the fire when Jonouchi and Hiroto Honda opened the doors (and were disgusted to find out that they rescued Bandit Keith).
Waking the Dragons
Keith was never seen following his time as Marik's mind slave, except as a lost soul in Season 4, Waking the Dragons, as a lost soul alongside those of the Player Killer of Darkness, the Rare Hunter, the Meikyu Brothers, Pandora the Conjurer, and Yami Marik, however, as most of them (aside from the Player Killer of Darkness, the Rare Hunter, and Yami Marik) were neither dead, in the Shadow Realm, nor taken by the Orichalcos, it is likely that this was just an illusion. It is possible, however, Keith was sent to Hell by Marik after he had failed him.
Yu-Gi-Oh! Falsebound Kingdom
Bandit Keith appeared as a minor villain in Yu-Gi-Oh! Falsebound Kingdom. He appears only in the Kaiba Campaign and you must battle him twice. Kaiba and Mokuba fight him first in the second level "Bandits". He appears along with Ghost Kotsuzuka who are wanted for robbery by the Emperor. Once they are defeated, Keith escapes and Kotsuzuka is left for dead but Mokuba lets him live and he becomes a permanent member of Kaiba's party for the remainder of the game.
Later, when Scott Irvine captures Mokuba, Kaiba did not know who took him and learned that Bandit Keith held onto him for awhile. You fight him again in "Bandits, Again" but he has three of Scott's soldiers with him. Once they are all defeated, Keith tells Kaiba that he gave Mokuba to Scott. It is unknown if this was the real Keith or a hologram created for the game. Since his deck consisted of machine monsters in the anime, he used machines in the game. The first match, he used Machine Sergeant, Commander and Cannon Dharma. The second time he uses Revolver Dragon, Slot Machine AM-7 and TM-1 Launcher Spider, which all three will join Kaiba's deck when Keith is defeated.