It’s a generally accepted fact that the emergence of the Flash in 1956 heralded the start of the Silver Age of Comics. Tasked with bringing superheroes back to National, editor (and Science Fiction agent) Julius Schwartz hired writers Robert Kanigher and John Broome and artist Carmine Infantino to spearhead the re-imagined Flash. Barry Allen, Central City police scientist (decades before the popularity of CSI), was struck by lightning one night while in his laboratory where the combination of the electricity and chemicals transformed him into the Scarlet Speedster, the Sultan of Speed, the Monarch of Motion, the Flash: Fastest Man Alive. When the Justice Society would be updated in the Justice League, it was a no-brainer right after the Trinity, the Flash would be on the team as a founder. And while the World’s Finest were generally absent in the beginning, the Flash and Green Lantern (who would become best friends) were very much the stars of the team title. Perhaps for these reasons, the Flash is the first shown member of the League to be elected the group’s chairperson. The Flash would be in good standing with the group until the apparent death of his wife Iris. Subsequently, he would murder her believed killer Professor Zoom the Reverse-Flash. Upon being acquitted of the crime, the League voted for the hero to remain in the JLA. Some time later, the Flash sacrificed his life in the Crisis on Infinite Earths.
Following Barry Allen’s death in the Crisis, his protege Wally West (Iris’ nephew) would inherit his mantle. When a new Justice League title was being put together, the Flash was one of the characters off-limits to the writers. Instead, Wally stumbled in his new role as the Flash for some time, eventually joining Justice League Europe (where he developed a confrontational relationship with fellow new Leaguer Power Girl). After some time there, Wally would join the Justice League Task Force but abandoned the group following the outcome of their first mission. Justice League America would briefly enlist the aid of the Golden Age Flash Jay Garrick around that time. Briefly, the JLTF would recruit Impulse (Bart Allen, Barry’s grandson from the future). Following Zero Hour: Crisis in Time!, Wonder Woman would reform a new Justice League America which included Wally. However, sales of the Justice League titles would continue to lag leading into Grant Morrison’s Big 7 JLA. Therein, while one of the younger team members, Wally West as the Flash was undoubtedly one of the group’s most devastatingly powerful members, doing things with his abilities no other speedster in prior history had done (for example, in his solo book, he battled Superman villain Mongul and beat his opponent by vibrating his fist in such away it could make matter explode). Sadly, Wally would sacrifice his life to stop the evil Cobalt Blue.
Shortly after Wally’s death, a new Flash emerged and joined the League. Only revealing his identity to Superman in order to establish trust to serve in the JLA, the new Flash was Walter West, a parallel version of Wally from Hypertime (the post-Zero Hour version of Parallel Earths). Wally, however, later returns and he and his parallel self merge at some level (increasing Wally’s ability with his speed powers) as Walter must return to his world in order to prevent a calamity forming from his presence being on the wrong Earth. Later, when the Justice League Elite forms, the Flash acts as a member of both teams (considering his super speed), switching into a dark costume when in the Elite and is somewhat of a liaison between the two. Further down the line when Sue Dibny is murdered, Wally is let in on the secret of the League within a League and his mentor’s part in it. Out of respect for Sue, he decides to join them (despite conflicted feelings about his predecessor that would lead to a great deal of trouble when Wally goes down a road paved with good intentions). Zoom, a former friend and ally to Wally that became an unhinged time manipulator, miscarried Wally’s two expected children only for the babes to be saved through an adventure in time. Upon birth, the children had an immediate connection to the Speed Force (from which the Flash’s powers derive) and the hero and his family moved to another planet to treat complications that arose from this advent. Bart Allen, then Wally’s protege as Kid Flash, inherited the mantle of the Flash.
The events of Infinite Crisis had aged the teenage Bart Allen four years in an instant, suddenly an adult who in very short order was promoted from Kid Flash to the Flash himself. However, sales and criticism of the new direction was poor and Bart would be killed off with Wally brought back behind him. Further, Wally would return to the League (the group decided not to invite Bart into their ranks when he was active). During the events of Final Crisis, Bart Allen and Barry Allen would return from the dead. Wally would remain active in the League until Green Lantern and Green Arrow formed a rogue Justice League at which point Wally resigned to devote time to the Titans. Following a team-up with the Justice Society of America, Jesse Quick (daughter of the Golden Age Johnny Quick) would join the Justice League. Following the events of Flashpoint, Barry Allen continued to be a founding member of the League.