The Justice League is an organization made up of the greatest heroes on Earth.
In 2010, Batman was the leader of the Justice League, having been formally elected. However, he was not the only leader that the League has ever had, as its leadership is rotational. Other than the leader, all members of the Justice League are considered equals. In late 2015, Captain Atom became the leader, until July 4, 2016, when Black Canary took over. The current leaders are Kaldur'ahm, who has now taken the mantle of Aquaman, and Wonder Woman, who acts as co-chair.
The League is permitted to operate by means of a U.N. Charter. League members have no jurisdiction within the borders of nations that have not signed the U.N. Charter, such as Bialya.The League also has a relationship with the U.S. government.
After Green Arrow and Black Canary encountered Amazo in rural Connecticut, half the League, including the powerhouses Superman and Captain Atom, responded. Their presence nearly proved disastrous as Amazo was able to copy all their powers. Eventually, the android was dismantled.
With the Injustice League's plant creatures sprouting up all over the world, Batman made sure the entire Justice League fought them to draw attention away from the Team as they went for the Injustice League's headquarters in the Louisiana bayou. They eventually made their way there too to force them to surrender.
After the incident on Rimbor with six mind-controlled Leaguers, the entire Justice League was declared unwelcome in the sector surrounding Rann. Not having figured out what happened during the sixteen hours unaccounted for during their enslavement, the Justice League was initially unaware of this ban.
The League and the Team discussed an alien attack on the UN. From Adam Strange, they learned Kroloteans were behind Zeta-Beam thefts on Rann, and that the Leaguers were unwelcome there—six were even wanted criminals. The Team sent a squad to Rann, while the League and the Team set up strike groups to target Kroloteans on Earth.
After Mal Duncan alerted everyone that the main Krolotean hideout was found by Gamma Squad, all twenty-one active members of the League rushed to New Orleans. When they arrived, they saw Robin, Blue Beetle and Lagoon Boy had already freed the hostages, and the base was destroyed.
After Miss Martian discovered what the League had done in the missing sixteen hours, Captain Atom and John Stewart discussed what to do. John convened with the Guardians of the Universe, and they thought it best that the six Leaguers traveled to Rimbor to defend themselves. Hawkman accompanied his spouse, and Icon joined because he had experience with intergalactic tribunal law.
The general populace was not made aware that eight powerful members of the League were off-planet. The League and the Team set up a ruse, and Miss Martian and Superboy at times impersonated Martian Manhunter and Superman to keep up the impression that they were still at full strength.
The Hall of Justice was invaded by the alien gladiator Despero, who sought to best Earth's mightiest champions in single combat. Though the warrior was eventually defeated, the Hall was destroyed in the process. When the Reachambassador arrived to "help" by removing the force field Despero had placed around the Hall, he casually let slip the existence of the Watchtower before the news cameras.
Superman testified before the High Court of Rimbor, explaining, not for the first time, how the League was compelled to attack the planet. The trial remained ongoing as the League refused to bribe their way to freedom.
While most of the League continued to deal with the problems the Warworld created on Earth, Captain Atom, Captain Marvel, Doctor Fate and Rocket defended Earth from Mongul's attacks and launched a counter-assault on the Warworld's surface. Meanwhile, the Team infiltrated the satellite and disbaled it.
After Miss Martian, Superboy and Adam Strange presented new evidence—a video recording of the Light admitting their subjugation of the League—and convinced the Tribune of the future profitability of a fair verdict in the case, the accused Leaguers were found innocent and released.
A group of forty heroes, including all the Leaguers on Earth, gathered for a briefing on the plan to stop the Magnetic Field Disruptors planted by the Reach to destroy Earth. The heroes paired off and attacked the MFDs simultaneously. Within thirty minutes, the twenty MFDs were disabled.
Captain Atom turned over chairmanship of the League to Black Canary. Later, Batman, Canary and the Team's mentors gathered to tell the Team that they would now operate from the Watchtower beside the League.
Each member of the Justice League has a membership number, which is read out when they enter restricted areas of the Hall of Justice.With the exception of the seven founders, who have designations 01 to 07, these designations indicate the order of the members' induction into the League.For the founders, their designations indicate the order in which they had arrived to battle the Appellaxians, before the League was formed.