|“||If you're going to hunt humans, you should know we travel in packs.||„|
|~ Joseph Korso|
He was voiced by Bill Pullman.
Joseph Korso was once an ally to Sam Tucker, the father of the protagonist Cale Tucker. He is the one who assigns Cale to search for the Titan. It is hinted in one scene that he is an ex-soldier because of how he stands.
He talked with the Drej Queen Susquehana, which is proof that in exchange for money, he is working for the Drej, an energy-based alien species that hated all organic life on the universe. Ironically, Korso is human, too.
Cale and Akima overhear a disagreement between Korso and the Drej Queen and discover that Korso and Preed are working for the Drej to try to destroy the Titan Project in exchange for money. Korso thinks the human race is doomed anyway and there is no hope; Cale and Akima escape from the Valkyrie, but she is wounded by Preed. They are stranded on the colony as Korso and the rest continue to the Titan's location. With the help of the other humans, Cale and Akima repair and refit the Phoenix, one of the colony's derelict spaceships, and race off to find the Titan before the Valkyrie reaches it.
Amid the Andali Nebula's giant ice crystals, Cale and Akima find the Titan. While exploring the massive ship, they discover a holographic message left by Cale's dead father, revealing the true nature of Project Titan: The ship is able to create a completely new, Earth-like planet, and has stores of all the DNA of the animal and plant life that once lived there. This was the reason the Drej feared humanity's potential enough to destroy Earth. Cale's father also explains that, after escaping the destruction of Earth, the Titan ran out of power and is unable to execute the recreation program.
The Valkyrie arrives, and Korso and Preed board the Titan, leaving a bomb to kill Stith and Gune (both of whom are unaware of their captain's true intents). Gune detects the bomb and attempts to get rid of it, but it detonates and Gune apparently perishes in the explosion. As Korso and Preed corner Cale and Akima and interrupt his father's message, Preed turns on Korso, revealing a more tempting deal; Preed will live (and get paid for helping the Drej find the Titan), providing that he kills the others before they arrive. Akima manages to disarm Preed before he knocks her unconscious, but Korso sneaks up from behind him and snaps his neck, killing him. Korso then tries to grab Cale's ring, but he falls into the depths of the Titan. However, he manages to save himself by grabbing onto a cable. The Drej arrive and begin attacking the Titan.
Surviving Preed's bomb, Stith shows up and the three work to defend the Titan from the Drej. Cale realizes that, by re-configuring the Titan, they can use the Drej to start the ship's reactor since they are pure energy. Korso, who had managed to climb back up and hide from the others, overhears this and realizes that he was wrong and that there is hope after all. Cale activates the circuit breakers, but only two of the three lock in place. The final one is jammed and fails to complete the circuit. Cale dons a space suit and goes outside to fix it. Outside, Gune, who also survived the bomb, uses the Valkryie's guns to fight the Drej.
As Cale reaches the breaker station, he is pinned by a Drej ship Gune shot down. Korso then appears before Cale with a large laser rifle. But instead of killing him, Korso blasts Cale free and says how they may be able to defeat the Drej after all. Korso tells Cale to get to the breaker while he provides him cover fire. Cale reaches the faulty breaker, but unfortunately, he still cannot fix it.
As the Drej prepare for a final attack, Korso tells Cale to activate the ship and he will take care of the breaker. Holding his gun as a bridge in the breaker, Korso jumps the circuit and starts the reactor, although at the cost of his own life.
- Joseph Korso was animated by Len Simon.