As Marvel's most popular X-Man, Wolverine was once difficult to picture on any other superhero team. Logan has cemented himself in the X-Men's corner of the Marvel Universe, despite the many different lives he's lived over the years. However, that all changed when Logan finally joined the Avengers in 2004.
Before becoming one of Earth's Mightiest Heroes, Logan already had a good history with a few of the Avengers and most of its members individually. In 1990's Uncanny X-Men #268, by Chris Claremont, Jim Lee, Scott Williams, Glynis Oliver and Tom Orzechowski, for example, revealed Wolverine's World War II history with Captain America and Black Widow. Additionally, Logan had a well-established friendship with Carol Danvers and Jessica Drew's Spider-Woman.
Still, Wolverine was never part of the traditional Avengers before the events of "Avengers Disassembled." However, Logan finally joined an Avengers team in 2005's New Avengers #5, by Brian Michael Bendis, David Finch, Danny Miki, Frank D'Armata, Richard Starkings and Comicraft's Albert Deschesne, where Wolverine encountered the New Avengers.
After the historical Avengers team disbanded, the New Avengers brought a looser group of heroes together. After running into this ragtag team in the Savage Land, Wolverine helped the New Avengers against Sauron and a group of rogue S.H.I.E.L.D. agents. Afterward, Iron Man offered Logan a spot on the New Avengers, despite Captain America's initial reservations.
Tony Stark suggested that, after the Scarlet Witch's mental breakdown, the Avengers needed someone who could make tough calls and go places the others couldn't, for the sake of the team and the public safety. Since Logan was still recovering from brainwashing at the hands of Hydra and the Hand, Stark also claimed that being an Avenger has given him perspective during tough times, which helped convince Wolverine to give being an Avenger a chance.
From this point forward, Wolverine had a place on both the X-Men and the New Avengers. Logan got to fight alongside traditional Avengers such as Captain America and Iron Man, while also working with other newer members like Spider-Man and Luke Cage. Wolverine was a good fit for this team, since, like most of its members. he was a relatively more grounded character than the gods and cosmic heroes the Avengers usually includes.
Wolverine's skills were particularly useful when the New Avengers became an outlaw group following the events of "Civil War." Logan was invaluable in fighting the Hand, the Hood's gang of super-criminals and the looming Skrull invasion. As times became darker for the New Avengers, Wolverine was the pragmatist that the group needed.
Even after the Superhuman Registration Act was repealed and the New Avengers were on the side of the law again, Wolverine stayed with the group, which continued on its own terms. Moreover, Logan joined the main Avengers team, fighting alongside heroes like Thor and cementing his place among Earth's Mightiest Heroes.
The event which truly cemented Wolverine's Avenger status was, ironically, "Avengers vs. X-Men," when Logan actually sided with the Avengers against his fellow mutants over how to best deal with the approaching threat of the Phoenix Force. This was a fairly big deal, considering his longtime ties to the X-Men, who Wolverine has considered his family.
At the time, Cyclops and Wolverine had gone through a major falling out. The point of conflict was also centered around the Phoenix Force, which Logan saw as nothing but trouble, while Cyclops saw it as a means to reignite the near-extinct mutant race. Ultimately, Wolverine stayed on the Avengers until the loss of his healing factor and eventual death.
Since his resurrection, Logan hasn't been an official Avenger, but his legacy hasn't been forgotten. For example, in 2021's Giant-Size Amazing Spider-Man: King's Ransom #1, by Nick Spencer, Roge Antonio, Carlos Gomez, Ze Carlos, Alex Sinclair and VC's Joe Caramagna, Wolverine was part of the New Avengers reunion, helping Spider-Man against all of New York's super-criminals. Even though he was on the main Avengers team, Logan remains a New Avenger at heart, with the gritty. grounded team having provided him an ideal way to step into the world of Earth's Mightiest Heroes.