Even before the success of the Marvel Cinematic Universe, the role of Captain America was defined by Steve Rogers. The embodiment of the American Dream past and present, Rogers' idealism made him stand out against some of the more nuanced characters in the Marvel Universe.
This would eventually cause him to clash with his own country, however, forcing him to give up the iconic title. Taking up the mantle in his stead was a brash and boisterous man named John Walker, who was everything that Steve wasn't. With the character getting more focus than ever in the lead-up to his MCU debut, here's a look back at when John Walker became the All-New, All-Different Sentinel of Liberty.
Debuting in 1986's Captain America #323, John Walker was created by Mark Gruenwald and Paul Neary. There, he was a sort of anti-villain named Super-Patriot who had been given superhuman physical powers that surpassed those of Captain America. He openly criticized the Star Spangled Avenger, who he saw as outdated and unfit to represent the nation, going so far as to try to goad him into fights. Nine issues later, Steve Rogers would abandon the role of Captain America, not wanting to be tied to the political agenda of the Commission on Superhuman Activities that now tried to control him. With neither Nick Fury or Sam Wilson deemed suitable to take up the mantle, the commission decided that Super-Patriot would be the next best man for the job.
Aiding Walker is his fight as the new Captain America was Lemar Hoskins, who temporarily acted as a new Bucky until he realized how unintentionally offensive the name was for a black man to bear. Renaming himself Battlestar, he and the new Captain both tried their best to emulate Steve Rogers' morals, though Walker was far more brutal and violent. This was exacerbated by both his great strength and rage still being not quite under control. He would even mercilessly kill villains such as Professor Power, though he grew to regret the terror he instilled in his enemies.
John Walker's already less than stable psyche would be irrevocably damaged when two ex-partners, now named Left-Winger and Right-Winger, revealed his secret identity to the public. This resulted in the murder of his parents, which is made worse when Walker can't even attend their funeral due to other obligations. Walker exacts his revenge by almost killing Left-Winger and Right-Winger, though the members of the Watchdogs militia group that killed his parents aren't so lucky. Enraged and illogical, the new, much more violent Captain America was captured by the villainous Flag-Smasher. He was eventually saved by Battlestar and Steve Rogers, the latter of which now using a new costume and calling himself "The Captain".
Captain America and The Captain are forced to fight each other due to the machinations of the revived Red Skull, who now lives through a cloned body of Steve Rogers. Though Rogers defeats Walker, it's Walker who ultimately beats the Red Skull.
Seeing the original man in action and no longer confident in himself, Walker persuades Rogers to take back the mantle of Captain America. The Commission wishes to keep Walker as a valuable asset, but they also realize how volatile he is in his current state. In order to make a better super-soldier out of him, they hypnotize him to make him forget his parents' deaths, all the while having him publicly fake his own and giving him a new identity of Jack Daniels. From there, he would go on to bear the name U.S. Agent, with a costume reflecting both Rogers' tenure as The Captain, as well as Walker's own nature as a dark reflection of the one true Captain America.