|First appearance||Astonishing Exiles #1|
Little is known about James's past except that Tony Stark is his adopted brother and James inherited some of his fortune. After Tony's death James became the armored hero War Machine.
James was plucked from reality by a being called the time broker. He told him as well as the others that something had gone wrong in his reality and they must work together to fix it. On their first mission they were sent to a reality where Magneto and his Brotherhood of Evil Mutants fought and won World War 2. They now rule the planet and their mission was to kill Magneto and end his reign. James pursued Magneto while the others kept the Brotherhood busy. James took of his armor so that Magneto could not control him. During their hand to hand combat James injected poison into him and completed the mission.
Their next mission was in a reality where Captain America was thawed out in the year 2099. They had to help the Avengers 2099 to defeat the Alchemax Enforcers and kill Walker Sloan before he can travel through reality and form his own Exiles. James fought his own Alchemax clone while Jen took care of Sloan.
Their next mission was in a reality where Spider-Man was an agent of S.H.I.E.L.D. Their mission was to make sure he died in battle against Baron Octopus. James convinced Peter to help them attack Baron Octopus so he could die and they could continue.
Their next mission was in a reality where the Fantastic Four consisted of Peter Parker/Pyre, Susan Storm-Parker/Elastic Woman, Johnny Storm/Nowhere Man, and Hank Pym/Beast. The two Johnny's became best friends. Their mission was to kill Reed Richards, who was the leader of the Frightful Four. Once again War Machine ends this mission by shooting Reed in the heart.
Their next mission was in a reality where every superhero except Colossus had been turned into a monstrous sombie. Their mission was to wipe out the zombie plague. During the mission Colossus was zombified. Phoenix was the one to activate the device that blew up all the zombies.
Their next mission was in a reality where Professor Xavier shared Magneto's dream and he helped him form the Brotherhood. Their mission was to form this reality's X-Men and get Professor Xavier to join them. Angel convinced him in the end.
The Exiles went on many more missions and he would eventually give up leadership to Phoenix.