Batman is such a reader magnet, it's hard to believe he wasn't always in every Justice League. Today he's part of two Leagues, the no-modifier A-list team (which we'll call "JL Prime" to avoid confusion) and the more eclectic Justice League of America. He also presides over an unrelated Gotham-centric team in Detective Comics. His membership in Justice League Prime reinforces its elite status, while he's more of a mentor to the new JLA.
The situation isn't entirely new. DC has had multiple Justice Leagues off and on for almost 30 years now. In fact, Batman was on two of the New 52's three inaugural League titles, JL Prime's Justice League (written by Geoff Johns and pencilled initially by Jim Lee) and the reimagined Justice League International (written by Dan Jurgens and pencilled initially by Aaron Lopresti). It didn't last long, as we'll see below; and it highlighted the tensions peculiar to these circumstances.
Capable as he is, however, we think Batman's close to the point where he might have to choose a League -- so we're here to help.
The League's Favorite Loner
Although Batman was a founding member of the Justice League (as related in February 1962's Justice League of America issue #9), he had only a cameo in its first appearance (February-March 1960's The Brave and the Bold issue #28). Still, he showed up regularly in Justice League of America until July 1983's issue #216. That same month, a special preview in Brave and the Bold #200 introduced his new team, the Outsiders. After leading them for a little under three years, he returned to the League (which had since entered the "Detroit era") in May 1986's JLA issue #250.
Except for a few years here and there, Batman has been a League fixture ever since. In fact, he tends to leave the various Leagues well before their natural ends; and he tends to be involved initially with whatever follows. Batman missed the last couple of years of Keith Giffen and J.M. DeMatteis' Justice League International era, but rejoined (largely in an advisory role) when writer/penciller Dan Jurgens relaunched Justice League America. He also guest-starred in the first arc of the concurrently-relaunched Justice League Europe (written by Gerard Jones and pencilled by Ron Randall). Nevertheless, Batman left again in 1993, when the Death of Superman storyline shook up JL America and the Knightfall saga took Bruce Wayne out of costume. Nevertheless, a wheelchair-bound Bruce did put together a team in October-November 1993's Justice League Task Force issues #5-6.
Batman returned to the League in September-November 1996's Justice League: A Midsummer's Nightmare, as part of a relaunch emphasizing the original big-name roster. That miniseries led into the ongoing JLA (1997-2006) from writer Grant Morrison and penciller Howard Porter. Although the creative teams and the memberships changed over the years, JLA and its successor Justice League of America vol. 2 (2006-2011) revolved mostly around the "trinity" of Superman, Batman and Wonder Woman. This changed dramatically with Batman's apparent death in 2008-09's Final Crisis, as May 2009's JLofA #31 had the team disband. Ten issues (and some diverse, innovative lineups) later, writer James Robinson had Donna Troy recreate the League once again, using a core of old Titans teammates like then-current Batman Dick Grayson. This version of the League was around for some 20 issues, until the series ended with October 2011's issue #60. The New 52 followed, with Dick back as Nightwing and Bruce back in the Justice League (and in the new JLI).