The group was originally founded to stop Lex Luthor and his Level 33.1 project(s), located around the world. This founding team included Green Arrow, Cyborg, Impulse, and Aquaman, as well as Boy Scout and Watchtower (who at that time were part time members). Together they successfully neutralized many of LuthorCorp facilities, stopping LuthorCorp's testing on meteor-infected people.
In 2007, Black Canary joined the team after initially being tricked by Lex Luthor into fighting the League.
In late 2008, after a global search to find Clark after the Fortress of Solitude was destroyed, LuthorCorp (now headed up by Tess Mercer, after the disappearance and later death of Lex Luthor) discovered the secret identities of Aquaman and Black Canary. Shortly after, the team decided to back off of LuthorCorp for a while and disbanded.
In early 2009, the group attempted to save the world by sacrificing the life of Davis Bloome, the camouflage of the monster Doomsday, only to almost get them all killed. By the time they buried Doomsday underground, Jimmy Olsen had lost his life. After the death of Jimmy, the group scattered all across the world. Oliver, who took it very hard, pursued a global venture of excess and debauchery, in an attempt to mask his pain. Chloe, realizing the need to protect the world against Tess Mercer and LuthorCorp, reunites the team to encourage Oliver to become Green Arrow again. Oliver soon realizes that the war against evil is larger than his personal self-interests and how important his role in that endeavor can be.
In 2010, they teamed up with the long retired Justice Society of America to stop the notorious hitman, the Icicle (a pawn of the secret government organization Checkmate) from killing all of the JSA's members. John Jones's re-gained his powers right before Doctor Fate sacrificed his life and allowed Icicle to kill him. The teams battled Icicle and defeated him. Checkmate also tried to get the team to work for them (as they tried with the JSA years before), but Martian Manhunter erased Amanda Waller's memory of their identities. The team, once again, teamed up with the Justice Society to battle the Kandorian army. When the Blur, now the established leader replacing Green Arrow, told them that he was going to send them (and himself) away, Cyborg told him that, as one, they would protect the world in his absence. When the Blur went to take them away, he was stabbed by General Zod with a blue kryptonite dagger, which suppressed his Kryptonian powers and prevented him and General Zod from leaving with the rest of the Kandorians.
Rick Flag, leader of the Suicide Squad survived Zod's attack on Checkmate and put together a new Suicide Squad and kidnapped Green Arrow forcing Watchtower to sacrifice herself in exchange for Green Arrow before faking her death. Flag later tried to recruit Green Arrow to his cause to prevent the Vigilante Registration Act from happening. In Watchtower's absence, The Blur and Green Arrow welcomed former enemy Tess Mercer into the team as the new Watchtower. With the VRA continually causing public fear and hysteria the heroes had been forced underground but came back together to mourn the loss of Hawkman who died protecting Lois Lane from Slade Wilson. While at Hawkman's funeral they are captured by the VRA. Chloe returns and with help from the suicide squad (who now work for her) helps the team escape the virtual reality the VRA trapped them in
|Image||Code Name||Real Name||First appeared|
|Boy Scout, Red-Blue Blur, Blur, Superman||Clark Kent||Missing Blur|
|Originally not a full time member, he has become more accustomed to working within the team and has become the official leader. Clark got imprisoned in the future at the beginning of season 1 and soon gets freed by Supergirl, Green Arrow and Aquaman.|
|Green Arrow||Green Arrow||Missing Blur|
|The League's founder and former leader. He provides funding for the League using his vast wealth, supplying tech to Watchtower to keep an eye on the world. He lacks extraterrestrial capabilities and is the only to have revealed his secret identity to the world.He has been the longest lasting member from small ville seasons .Green arrow later becomes the leader again when Clark goes missing|
|]||Martian Manhunter||John Jones||Missing Blur|
|Joined the team recently after permanently basing himself in Metropolis as a detective, John regained his powers and is now an integral part of the team, providing cover with the police. John usually keeps the watchtower safe whilst the others go on missions and sometimes field missions|
|Black Canary||Black Canary||Missing Blur|
|Originally a gun for hire attacking the League, she joined the cause after being exposed to the truth and is considered an important player in the League. Dinah is a full time member of the justice league when Clarke goes missing|
|One of the first members recruited for the League by Green Arrow, Aquaman is the team's dominant water based hero. Aquaman is a part time member of the Justice League since he has a life in Atlantis|
|Impulse||Impulse||Losing Our Way|
|He is the hothead of the League used for getting and stealing information with his super speed. Like Clark, Bart seems to have multiple code-names, as he has also been referred to as The Flash in one of his latest appearences. Impulse is a series regular.|
|:Kara is based in the future with the Legion of Superheroes after Smallville seasons. and is a part time member of the Justice League in the present. And future|
|Stargirl||Stargirl||All Hope Lost|
|The youngest member of the team, step-daughter of Pat Dugan and Sylvester Pemberton's successor, for a short time she worked with the reformed Justice Society of America, but switched teams after attempting to recruit its former members. Stargirl helps out on missions when she can|
|Zatanna is revealed to be a member in Icarus. She has helped out on occasions. She also mentioned to Oliver that if he ran into any dark magic, he can give her a call, and she would be willing to help. Zatanna becomes a full time member when Clark is kidnapped.|
|Image||Codename||Real Name||First appeared|
|||'Watchtower'||Chloe Sullivan||Where's Superman?|
|Chloe Sullivan, as Watchtower, was the team's eyes and ears around Metropolis and the rest of the world, providing information and access to each member and was considered the unofficial leader coordinating each League member with a mission. She recently returned to the team after a long absence, and was revealed to be in control of the Suicide Squad. In Fortune she officially resigned from her role as Watchtower. She currently resides in Star City and works as a recruiter for future heroes. However, it was discovered in Finale Part 2 she still operated as a part of team during emergency scenarios.|
|||'Hawkman'||Carter Hall||The Hawks|
|Hawkman was the leader of the Justice Society and apparently a member of the Justice League. He sacrificed his life to save Lois Lane in a battle with Slade Wilson. It is revealed that Hawkman is still alive and is found being held captive by Lex Luthor.|
|Cyborg||Victor Stone||Losing Our Way|
|Victor Stone was a part of the original Justice League in Smallivllle seasons but has now became a support member.|
This is a list of people who the League has encountered, but either are not League members or have a heroic identity.
|Image||Codename||Real Name||First appeared|
|||'Doctor Fate'||John Zatara||Ressurection|
|Was the one member of the JSA that did not become part of the team. He died in battle with the Icicle after saving John Jones' life. It turns out that Doctor Fate got repossesed by the ressurected John Zatara.|
|||'Mera'||Mera||Starro Attack Part 1|
|Aquaman's wife helped the League against Slade Wilson. She rescued both her husband and Oliver from captivity.|
|||'The Suicide Squad'|
|After Chloe went missing she contacted the team and gave them choice of being turned into the government or reporting under her lead. The two members that assisted were Rick Flag and Deadshot.|
|||'Booster Gold'||Booster Gold||Through Time We go|
|After Clark helped Booster realize what it truly means to be a hero, he repaid the favor by upgrading the systems in Watchtower based on his and Skeets' knowledge of technology from the future. Booster Gold helps out in some Missions in The Justice League new seasons.|
|A mercenary hired by Chloe to help the League get Oliver out of his downward spiral. She devised a "game" that in which the League would rescue Oliver from her tests until Oliver stood up and embraced his inner hero. She knew Oliver's identity before it was public knowledge, and later appeared in Prophecy, where she planned to use her knowledge of her clients' identities against them as a Member of Marionette Ventures.|