US Agent's History
Early Life
John Walker grew up idolizing his older brother Michael, who had been killed during the Vietnam War. He went into military service but felt he wasn't a 'hero' like his brother was. Walker underwent the Power Broker process to compete in the Universal Class Wrestling Federation. However, his agent convinced him that he should become a hero.
Super-Patriot
He became the Super-Patriot, arguing that he stood for America's 'true ideals' and began to publicly discredit Captain America. Three 'Bold Urban Commandos', fellow recruits from the Federation, assisted him by staging attacks and intimidating others.
After a fight with Captain America at a rally in Central Park, Walker killed a terrorist named Warhead who threatened to detonate a nuclear weapon in Washington, D.C.
Captain America
Captain America later abandoned his identity due to Red Skull's manipulation of the Commission on Superhuman Activities. Walker took the role as Captain America, moderating his views. The man who would later become Battlestar served as his Bucky. The other two BUCs became Left-Winger and Right-Winger.
Left-Winger and Right-Winger publicly revealed Walker's name leading up to the Watchdogs killing his parents. Walker retaliated by killing most of the Watchdogs. He captured Left-Winger and Right-Winger and used his old 'torchsword' to ignite explosives they were strapped to, leaving them horribly burnt and in comas.
Eventually there was a confrontation with Captain America who was then calling himself the Captain. Walker was stopped by Rogers. The two confronted the Red Skull, who had been manipulating the Commission. In light of these events, Walker was deemed unworthy of the Captain America title due to his actions.
U.S. Agent
Walker's death was soon faked by a member of the Commission and he re-emerged as US Agent. He wore a variation of the costume that Rogers had worn as the Captain and using his vibranium disc as a shield. Walker continued to work for the Commission. He was first seen as the U.S. Agent battling an Iron Monger, as a test for the Commission. Walker was additionally placed as a watchdog of Avengers West Coast and the Vision by the Commission, as a condition to possibly get their government clearance reinstated. He later rescued his former partner Battlestar from the Power Broker, and reconciled with him; John learned that his memories had been altered and that his parents were dead.
Force Works
When the West Coast Avengers dissolved, his costume and shield into the Hudson River. Tony Stark formed a new team known as Force Works. Initially reluctant to join however Scarlet Witch later persuaded him to join, she believed John was the team's backbone. He intended to run the team on tight military lines and the values of strength and dedication. John ultimately joined the team, wearing a new costume and using an Energy Shield. John remained a member throughout the team's tenure, fighting threats such as the Kree, alien parasites the Scatter, the supernatural threat Ember, Slorenia's armored protectors Black Brigade, and The Mandarin. They went on to fight alongside Australian super hero Dreamguard against the dream-manipulating Orphan, Slorenia's undead shock troops The Targoth, and Volkhvy the Eternal One. They teamed up with the Avengers against the Kree commandos Excel. They later went up against intergalactic mercenary the Broker. They even had to fight their security system V.I.R.G.I.L., and an alternate reality version of deceased former Force Works member Wonder Man.
Working for his old Commission ties led him into conflict with other heroes. Walker seemed to have finally cut ties with them after one mission put him into conflict with War Machine and Hawkeye.
The Jury
John eventually became the field leader of the Jury, a group of armored corporate vigilantes owned by Edwin Cord, owner of Cordco. U.S. Agent again wore his original U.S. Agent uniform and used an eagle-shaped shield that could be directed in mid-air via remote control. The Jury's job was to take down the Thunderbolts, but they were defeated by the Thunderbolts and their new leader Hawkeye. The Jury attempted to apprehend the Thunderbolts a second time, but instead the two groups joined forces together against Brute Force and the soldiers of the Secret Empire.
U.S. Agent was later severely beaten to near death by Protocide. Due to emergency medical procedures performed on him, he was outfitted, by S.H.I.E.L.D., with an enhancing exoskeleton.
S.T.A.R.S.
Walker eventually appeared in Texas working on behalf of the US Government as leader of S.T.A.R.S. to arrest Piledriver for attempting to escape to Mexico and act as international representative of US interests. Walker acted as the leading figure on behalf of the US government in their cooperation effort with the Avengers, but was greatly disliked due to his abrasive behavior and domineering personality. Walker convinced a number of alien convicts to fight on his behalf for their freedom and led the charge against the Kree and Ronan the Accuser. Walker stalled Ronan while the Avengers stopped his plan to use Ego the Living Planet as a weapon by assimilating the Earth. After the Kree were defeated, the Avengers tried to thank Walker but he rebuffed them and rebuked them for letting the alien threat be drawn to Earth in the first place before leaving.
The Invaders
Walker joined the new Invaders squad acting as its Captain America; he in fact demanded to be called by that name. Those Invaders who knew the real Captain America refused to do so. He claimed that today's world requires a tougher symbol of America to battle terrorism. Alongside the Invaders he battled Axis Mundi. When the Human Torch (Jim Hammond) was killed, most of the team disbanded.
Civil War
John favored the Superhuman Registration Act, and was assigned to Canada as an official liaison and reluctant leader of Omega Flight - A number of powered villains, including the Purple Man, attempted to cross the border into Canada to escape the act and then the Wrecking Crew who came to Canada to continue their life of crime without superpowered opposition and ended up freeing the Great Beasts.
During this time U.S. Agent was also given the responsibility of keeping an eye on and training Guardian (Michael Pointer and discovered that Pointer was being used and experimented on.
Mighty Avengers
He was recruited without warning by a seemingly recovered Scarlet Witch to a new team of Mighty Avengers. The Scarlet Witch was actually Loki in disguise.
Retirement
Sent into battle against Norman Osborn's black-ops Thunderbolts team in Asgard, Walker's left arm and leg were severed by Thunderbolts leader Nuke/Scourge. Retired from active duty and fitted with a metal hook for a prosthetic hand (refusing better prostheses because he didn't want to become a cyborg like Nuke), Walker became the warden of the super-villain prison the Raft.
Back in Action
While transporting the Dark Avengers back to the prison, their transport went down and Walker and the team woke up in an alternate version of New York, divided in various territories controlled by heroes. While knocked out, June Covington who had managed to gain control over Hank Pym and had free rein in a laboratory, bonded Walker with that world's Venom Symbiote which had its higher brain functions removed. Being bonded with the symbiote restored Walker's lost limbs.
Leading the Dark Avengers, Walker attempted to find out what had happened to New York and reality. They found out from Reed Richards that A.I.M. were behind the alteration of reality, creating a distorted reality pocket to test potential scenarios and salvage technology created by the denizens of the pocket. The Dark Avengers managed to open a portal into the real world, where they crushed the A.I.M. agents. With the mission completed, and the Dark Avengers free, June used her powers to influence Walker into allowing them to remain free, and to lead them on further adventures.
John joined Doctor Doom's Avengers, and battled the now-evil Scarlet Witch who arrived to Latveria to have revenge on Doctor Doom. The Avengers fought the Scarlet Witch and saved villagers trapped in the crossfire. 3D Man managed to get hold of the Witch and take her to a machine Doctor Doom had created to specifically canalize her abilities. Soon after being put into the machine, the Scarlet Witch escaped and set out to find Doom, leaving the Avengers behind. After condensing a portion of Scarlet Witch's powers into the device, Valeria Richards informed the heroes their job was done.
Confronting Sam Wilson
Months later, John Walker rejoined the U.S. Army, and was sent on a mission in unknown locations in the Middle East taking down terrorist cells. After a raid at a terrorist compound, he got a call from the U.S. Senate. Soon after the mission was done, John went back to United States where he met with Keane Industries president, Paul Keane and Texas Senator Tom Herald in Manhattan. They explained to him that the reason he been contacted was to reclaim Cap's shield from Sam Wilson since he was not deemed suitable for the title of Captain America by the public. Keane and Herald also showed him news footage of Sam supposedly attacking the Americops.
While personally disagreeing on Wilson's political views and disapproving on how they influenced his actions as Captain America, Walker refused to confront Sam. However, they were interrupted by Steve Rogers, who asked to talk to John privately. Steve told John that the pressure of the job was causing Sam to go out of control as it did to John, and asked him to confront him personally. Walker then went to the scene of the fight and ordered Sam to hand over Cap's shield. Sam refused, and the two began fighting, with Walker's much greater physical strength giving him an early advantage. Sam managed to turn the fight around by forcing Walker into a dark tunnel and using his powers to get the aid from owls that lived in the tunnel, defeating him and leaving him on the pavement. Unknown to anyone involved, Rogers' history had been altered to make him an agent of Hydra from the start, and had engineered the whole conflict. The following week, it was reported that John went missing on a mission in Syria. He would resurface later on, as one of the countless heroes fighting Hydra's forces in Washington, D.C., following their takeover of the United States.
Robot Revolution
In the midst of the robot revolution, Force Works was reinstated and Walker was placed on the team. He, Quake, War Machine, and Mockingbird were sent to Lingares where they were met with an army of Deathloks and the giant robot Ultimo.[57] M.O.D.O.K helped them stop Ultimo, but only so he could take control of his body. After the team failed to retrieve data on how to build the Deathloks which M.O.D.O.K. made to fight Ultimo, everyone present besides Walker were removed from the team by Maria Hill. Walker instead gave a blank drive to Hill so she would go through with wiping Lingares clean of the Deathloks and the data.
