Quackerjack was once the owner of a profitable toy company, until he lost all of his money due to a rival company's record-breaking sales of the popular video game Wiffle Boy. Afterward, Quackerjack went insane, began talking to a Mr. Banana Brain doll, and, dressed as a jester, began committing acts of crime and sabotage such as blowing up a warehouse full of Wiffle Boy games. He attempted to sabotage a video game tournament in order to destroy "Wifflemania" once and for all, but wound up trapped inside the game where he was eaten by an alligator.
He later escaped, however, and joined Negaduck's Fearsome Five, although like Bushroot he still sometimes went solo. Quackerjack's evil schemes always revolve around toys, which he designs himself to have a variety of dangerous built-in weapons, and he finds humor in almost everything, including and especially the misfortunes of others. When a member of the Fearsome Five, he is usually paired off with Megavolt, who claims they "make an electrifying team."