Peggy was born April 9, 1919. After stints as nurse for the British Air Force, and service with the Special Air Service, she was assigned to the SSR in 1940.
In 1943, under the command of Colonel Chester Phillips, Peggy was assigned for the training and evaluation of several recruits and candidates for Project Rebirth, the creation of the first "Super Soldier".
Peggy eventually comes to bond with Steve Rogers, a spirited but physically frail young man who is ultimately selected as the first test subject. Peggy, having had her professional opportunities limited due to being a woman, identifies with Steve's determination to succeed and even finds herself charmed by his earnest, if awkward, attempts to converse with her.
Under the supervision of Dr. Abraham Erskine, the inventor of the Super Soldier Serum, and inventor-industrialist Howard Stark, the experiment proves a complete success, transforming Rogers into a near-perfect physical specimen, with near-superhuman speed and strength. Tragically, an act of sabotage by HYDRA spy Heinz Kruger leaves Dr. Erskine dead and serum lost, leaving Rogers the only successful example of his work.
Immediately thereafter, Peggy is informed by Col. Phillips that the SSR was being reassigned to Europe to fight HYDRA direct, with Peggy and Stark accompanying them. Rogers, for his part, would be sent on a nationwide campaign to promote the purchase of defense bonds in a flashy red, white, and blue costume, under the name "Captain America". When Steve begins to grow disillusioned with this role, Peggy reassures him by reminding him that Erskine had meant him for more than this.
When Steve plans an unauthorized mission to infiltrate a HYDRA base to rescue his friend Bucky Barnes, who was captured, Peggy and Howard fly him within parachuting distance of the base before enemy fire forces them to turn back. When Steve is believed killed, Phillips reprimands Peggy for her actions, predicting that it would lead to the SSR being shut down. Peggy, for her part, argues that she would have had faith in Steve, which proved to be well placed when Steve returns mere moments later, alive, not only with Bucky but also some four hundred other Allied POW's liberated from the base.
The subsequent fight against HYDRA (with Steve now leading the troops at the front lines) leaves Peggy and him little spare time to spend with each other, though she consoles him when Bucky is later lost and presumed killed in a fall during a mission to capture the HYDRA scientist Arnim Zola.
The two later participate in the final assault on the final HYDRA base in the Alps, when HYDRA leader Johann Schmidt assembles a massive bomber called the Valkyrie, powered by the Tesseract, to rain destruction on the major cities of the world. With Phillips' help, Peggy and Steve are able to catch up to the plane before it took off and get Steve aboard, though not before Peggy gives him a kiss for luck.
Sometime later, Steve radios in that Schmidt had been defeated, but that he altered the plane's course for New York City, and would be forced to crash it in the Arctic Ocean. Knowing this would mean his death, Peggy nonetheless tearfully indulges his talk of planning a date, before the plane crashes into the ice, cutting them off.
Shortly after the demise of Steve, Peggy, along with the Howling Commandos, come to Austria to arrest members of HYDRA, during the arrest Reinhardt warns Agent Carter that when one cuts a HYDRA's head two appear in its place. Later, Peggy interrogates Reinhardt. During this interrogation Reinhardt speaks of Blue Angels who come to Earth; believing he is crazy, Peggy sentences him to spend his life in prison.
A year after the war, Peggy is still working for the SSR. Despite being one of the most important members during World War II, her boss and colleagues treat it more as a secretary. She later is contacted by Howard Stark via his butler, Edwin Jarvis. Stark tells Carter that someone has stolen some of his experiments and need to recover them to clear his name. The next night, Peggy went to La Martinique to try to recover the formula of Nitramene but only discovers that they had already fabricated. After taking Nitramene from the safe of Spider Raymond, she manages to turn it off before it explodes. Having Off the Nitramene, she founds her roommate dead, then discovers a man with green suit, who fight for a few minutes.
The next day, she and Edwin Jarvis went to visit a colleague of Howard called Anton Vanko. Vanko tells them that despite to disable the Nitramene, this artifact continues to be volatile. The same night, Peggy with the help of Jarvis manages to enter to the facilities of Roxxon. There she discovers that the Nitamene already been mass produced. She is also informed that Leviathan is coming. After the mission, Peggy asks Jarvis to investigate what is Leviathan.
After the death of her roommate at the hands of Green Suit, Peggy becomes homeless. However, Edwin Jarvis offers to Carter one of Howard's penthouse. At first she refuses, but eventually she accepted. The next morning, Peggy learns that a photographer had taken a picture when she was in La Martinique. She tries to get that picture from Daniel Sousa's desk without success.
She later is called by Roger Dooley to scan the females who work in the Roxxon Corporation. That night, after facing Green Suit, Peggy gets a new home thanks to her friend Angie Martinelli.
One night, Peggy finds a man climbing to his apartment. This man was looking for his girlfriend named Molly, who the next day was kicked out from the hotel. She later helps Jarvis, who was being interrogated by Agent Thompson. After his "error" Dooley scolds her and asks her to apologize to Thompson. She apologizes to him, but Thompson does not accept her apology.
That night, Carter and Jarvis found the weapons created by Howard that had been stolen by Leet Brannis. Since this finding could not report directly Jarvis makes an anonymous call to report the find. While Jarvis was to make the call, she was faced with Zandow. The next day she learns about Krzeminski's death. A devastated Peggy went to L&L Automat to tell her friend Angie how it was her day.
Peggy along with Edwin Jarvis went to look for Howard Stark, who had returned to the country with the help of smugglers. As he did not have to stay, Peggy takes him to Griffith Hotel in secret. Stark then gives her a new mission: recover the Blietzkrieg Button from SSR. After hearing that Blietzkrieg Button was not a weapon but a container of Steve Rogers's blood, Peggy hits Stark for lying to her. Peggy then hides Steve Rogers's blood for does not falling into the wrong hands.
After the Remote Typewriter write a message, Dooley called Carter to translate it. Carter promised that the Regiment 107th were going to escort them only if she was involved in the mission, which Dooley accepted. While she is changing for the mission in the men's locker room, Daniel Sousa notices that Carter has a gunshot wound on her shoulder. Arriving in Russia, she and Thompson meet with the Regiment 107th better known as the Howling Commandos.
The next day, the team infiltrates the Red Room Academy. Here they find a film projector which shows films with subliminal messages. They also found a little girl, in a moment of distraction she stabbed Dum Dum Dugan and killed Junior Juniper by a gunshot. Later, they meet two scientists called Ivchenko and Nikola who were imprisoned in the Academy. The team frees the scientists before the Leviathan soldiers appears.
In a moment of madness, Nikola taken as hostage Happy Sam Sawyer; Peggy asks him to release her friend. Seeing that Nikola would not release Sawyer, Ivchenko shoots and kills his fellow prisoner. Back in the United States, Thompson invites Carter to have a drink with him. Peggy asks Daniel Sousa if he does not want to accompany them but he refuses the invitation.
As Dooley sent her to find potential spies women, Carter sought to Jarvis for help. They went to different residences of different women but none had a scar on his wrist. Meanwhile Sousa informed Dooley that Carter was the mysterious blonde woman from La Martinique. When she and Jarvis met at L & L Automat they were ambushed by agents of the SSR led by Thompson and Sousa.
Carter manages to defeat the agents who were inside the establishment. Outside they were cornered by Jack Thompson; however Carter was able to disarm him and knock him out. Suddenly, Daniel Sousa saw Thompson lying on the ground. He then asks her to surrender but she knew he was not able to shoot her. As she was right, he leaves her go. Carter went to the Griffith Hotel to obtain the Blitzkrieg Button.
Having achieved what she wanted, Carter was about to leave the hotel; suddenly Underwood appears and tells her that some agents are looking for her. Peggy told Underwood that she was very rushed, then the Russian spy kisses Carter and before losing consciousness she finds out that Dottie had marks on her wrists. After being arrested, Carter told Dooley that she explain it all.
She was questioned by Sousa, Thompson, and Chief Dooley. As Carter said nothing Dooley was very impressed. Suddenly, Jarvis went to the New York Bell Company to request the release of Carter as he acclaimed to have the confession of Howard Stark. When they were alone, Jarvis admitted Carter that the confession was false. At that precise moment, Carter saw as Ivchenko was communicating with someone in another building. Carter then decides to confess because it was the only way that Dooley and the other agents believe her. She confesses to Dooley the reason why she helped Stark.
Seeing that Dooley and the other agents didn't believe her, Carter showed them the content of Blitzkrieg Button (Captain Rogers' blood). After this act of sincerity, Dooley sent agents to arrest the person who was in the other building; while he was in charge to arrest Ivchenko. Jarvis and Carter later were locked in a room by Roger Dooley as Ivchenko hypnotized the Chief. They managed to escape but it was late Ivchenko had taken the Item 17 while Dooley was wearing the Self-Heating Vest. Before dying, Dooley asked Carter to catch Ivchenko, Carter accepted the final instruction of her boss. She watched as Dooley jumped out of the window and exploded in mid-air. Carter and the agents wondered what Ivchenko wanted. When they went to the lab, Doobin inform them that Item 17 was missing.
Carter, Thompson, and Sousa went to a cinema theater where a slaughter had occurred. Here, Sousa found the container of Item 17 and accidentally inhaled it. He attacks Thompson and Carter before being knocked out. Later, She explains Sousa what happened. When she questions the motives of Fennhoff, Stark appears and explains what happened in Finow. Stark offered himself as bait to lure Fennhoff, but the plan does not go as expected and Stark is kidnapped.
When she wondered where they had taken Stark, Jarvis admits that his boss had another hidden hangar. Then, Carter, Thompson, and Sousa went to the private hangar to save Howard Stark and capture Underwood and Fennhoff. She eventually finds Fennhoff and Underwood; Underwood and Carter fight while Fennhoff flees the scene. Carter manages to wake Stark from his trance after beating Underwood. The next day, Carter received a standing ovation from her colleagues in the SSR. However, Thompson received the credit from the President. Sousa sought that Carter received the credit but she was no more interested in what others thought. Sousa leaves out his shyness and asked Carter to have a date, she replied that on another occasion but she smiles thinking about it. As a reward, Stark gave Carter a place to stay. She chose Angie as a housemate. Being alone, Jarvis gave Carter Rogers' blood since for him she deserved decide what to do with it. Carter then went to the Brooklyn Bridge and said goodbye by pouring blood into the water.
In a video documentary, an older Peggy talks about her life after the end of the war, where, by 1953, she had married, ironically, to a man whose battalion had been saved by Steve, and later had children. It is also shown that she along with Phillips and Howard would convert the SSR into a new intelligence agency known as S.H.I.E.L.D..
In 2014, Steve reconnects with Peggy, who was living in a nursing home. While the two talk, Steven confides in her his difficulties adjusting to the new world and admitting that service (now under S.H.I.E.L.D.) wasn't quite what it used to be. Peggy reminds him that the world had changed but many do their best, which sometimes meant starting over. Sadly, by this point, Peggy had developed Alzheimer's, which leads to her forgetting Steve when he turns away for a moment, then reacting with shock and joy that Steve was alive when he turns back.
Peggy makes an appearance in the film's beginning. Depicting the events of 1989, she is present with Howard Stark and Mitchell Carson when Hank Pym resigns from S.H.I.E.L.D. after Pym discovers the organization was trying to replicate his technology. Peggy and Howard try to convince him to reconsider, but Pym ignores them and he leaves.
In 2016, Peggy passes away at the age of ninety-five. Steve is informed by Peggy's niece Sharon Carter that Peggy died peacefully in her sleep.
- Hayley Atwell based her performance as Peggy Carter on Ginger Rogers: "She can do everything Captain America can do, but backward and in high heels."
- Before Hayley Atwell was cast as Peggy, Alice Eve, Gemma Arterton, and Keira Knightley were considered for the role of Peggy Carter. Emily Blunt turned down the role.
- Peggy was originally going to appear in The Avengers, in which she encounters Steve in the present day, but it was ultimately cut from the final film by director Joss Whedon.
- Hayley Atwell made a cameo appearance as an illusion of Peggy Carter in Avengers: Age of Ultron.