Sometime after WWII, Wolverine was abducted and made a part of the "Weapon X" program. During this time, an indestructable metal called adamantium was grafted onto Wolverine's bones. He was also given three foot-long claws on each hand. He is able to retract back into his arm at will. This adamantium bonding procedure would have killed an ordinary man; Wolverine, however, was saved by his healing mutation. Wolverine eventually escaped from the laboratory where the Weapon X experiments were being conducted, and joined the Alpha Flight, the Canadian government's superhero group.
While working with Alpha Group, Wolverine was contacted by Professor Charles Xavier. Xavier was looking for mutants to come with him to rescue his captured team of mutant-students, the X-Men. Wolverine agreed, and after the successful rescue of the X-Men, decided to join the team (partially because he had fallen in love with Marvel Girl, a.k.a. Jean Gray). Alongside the X-Men, Wolverine fought against Magneto and his Brotherhood of Evil Mutants.
During a battle on the space station Avalon, Magneto used his magnetic powers to rip the adamantium from Wolverine's bones and out of his body. Wolverine, who thought his claws had been provided by the Weapon X program, was startled to find that his claws were actually bones that had also been coated in metal.
At one point, a mutant called Genesis attempted to regraft the adamantium to Wolverine's bones. His body rejected the procedure, causing Wolverine to become almost animal in nature. He remained this way, living in the Canadian wilderness, until being brought back to humanity by Elektra.
Wolverine is currently not a member of any organization, and is residing somewhere in the Canadian wilderness.