Margaret Carter

"The world has changed, and none of us can go back. All we can do is our best, and sometimes, the best that we can do, is to start over."

- Peggy Carter to Steve Rogers

Margaret "Peggy" Carter was a British officer representing the Strategic Scientific Reserve and Steve Rogers's World War II girlfriend. And after the war, She along with Howard Stark founded S.H.I.E.L.D. with Colonel Chester Phillips.

Captain America: First Vengeance
Margaret Carter was an agent of the British Secret Intelligence. In November 1940, she infiltrated Castle Kaufmann, the headquarters of the SS general Johann Schmidt, leader of HYDRA, Adolf Hitler's top secret science division. Disguised as a maid Eva, she freed the captured scientist Abraham Erskine and brought into the Strategic Scientific Reserve.

Captain America: The First Avenger
Peggy served as an Operations Supervisor to the Strategic Scientific Reserve. While training several candidates for Project Rebirth, she came across a frail-bodied young man named Steve Rogers, who Dr. Erskine was intent on becoming the project’s first human test subject, due to his goodhearted nature and great will to serve his country. Although initially skeptical of him because of his appearance and weak health, Peggy eventually saw that Rogers was smarter and more practical than the rest of the potentials, and was often amused to see the smaller man outwit the burly recruits. She was impressed and developed respect for him when, during a test, Rogers chose to muffle a grenade with his body, not knowing it was a fake. It was this choice that inevitably led the SSR to approve Erskine’s choice to make Rogers Project Rebirth’s first test subject, and Peggy was tasked to escort Rogers to the laboratory when that time came.

After Project Rebirth proved to be a success, Peggy developed a crush on the physically-enhanced Steve Rogers, though she referred to it as "having faith in him." However, following Dr. Erskine’s murder and the loss of the last copy of the serum, Peggy went on with the S.S.R. and was separated from Rogers, who was sent to tour America and became a famous icon amongst the masses as Captain America.

Peggy was reunited with Rogers when he flew to Italy to advertise war bonds and attempt to boost morale. She was unofficially on-site at the time and soon discovered that Rogers was feeling stifled once more, wanting to use the gifts Dr. Erskine had given him to serve his country as a soldier. Their conversation was interrupted when an ambulance arrived and Peggy let slip that the injured soldiers were from the 107th, at which Rogers instantly rushed to see Colonel Chester Phillips and demand the status of his friend, Sgt. James "Bucky" Barnes. Phillips confirmed that Barnes was missing, and when Rogers learned that no rescue mission was being planned, Peggy realized he was about to do it himself. Wanting to give him a fighting chance, she helped him enter enemy territory by cajoling Howard Stark into flying them there.

Later, she entered Phillips’s tent in time to hear him declare Rogers dead, after which Philips reprimanded her for her part in Rogers’s scheme. Before he could finish, a commotion drew them both out of the tent, where they found Rogers leading the formerly HYDRA-captured troops back to base.

After his incredibly successful rescue, Rogers was drafted into the S.S.R. and began to serve in a more active capacity, putting him in close contact to Peggy, who tried to remain professional around him. Her attempt largely failed when she caught him and a female lieutenant kissing, leading her to shoot him while he was trying out a new shield. She was, however, quite pleased when a film of Rogers' efforts in the field revealed that he kept a picture of her in his compass.

Following the death of his friend Bucky, Peggy found Rogers attempting to get drunk in a bar she had once found him and Barnes in. She informed him that Dr. Erskine had presumed his body processed the alcohol too fast, preventing him from his goal, then told him to respect Barnes’s choice of following him until his death.

When the S.S.R. planned for a full-frontal attack on HYDRA, Peggy went along, saving Rogers from a soldier wielding flame-throwers before reminding him to go after the Red Skull. She and Colonel Philips later appeared in Schmidt's car to help Rogers get to Schmidt's plane, The Valkyrie, which was already leaving the hangar.

Following their defeat of the remaining HYDRA soldiers, Rogers called in, reporting that Red Skull was dead but that the plane was heading for New York with no way of stopping it. Rogers decided to put the large plane in the water. Peggy, believing that this would result in his death, doesn't give up hope and insists on the matter, implying that there would be time for them to sort the situation out. Rogers claims that there isn't enough time and proceeds with the landing, and Peggy attempted to distract him from his impending death by setting a date with him, promising to teach him how to dance.

Finally, The Valkyrie is found decades later, and in an unexpected twist, Steve Rogers was discovered to still be alive. The experiments that he underwent in the past had allowed him to survive in the ice, which had cryogenically frozen him, allowing him to retain his youthful appearance. Later, after Nick Fury reveals that he’d been asleep for almost 70 years and asks if he would be all right, Rogers mentions his date with Peggy.

Marvel One-Shot: Agent Carter
After catching the criminal known as Zodiac; Carter was invited to become a charter member of S.H.I.E.L.D. alongside Howard Stark and Timothy Dugan, much to the chagrin of her misogynistic peer John Flynn.

The Avengers
While training, Steve Rogers thinks back on his past, and has visions of Peggy and the other friends he's lost.

In the files Rogers studies, Peggy is reported as "Retired".

Captain America: The Winter Soldier
Peggy has since been married and had children. She is ill, and Steve visits her at the retirement facility. Although she initially appears to recognize Steve, she slips back into a state where she believes to be seeing him again for the first time since he was lost. Shocked to see him alive, she laments over how much time has passed. He merely says, "I couldn't leave my best girl. Not when she owes me a dance."

Avengers: Age of Ultron
To be added

Character traits
Agent Peggy Carter is a strong woman and a great agent, one of the first female agents in US Army. Because of her uncomfortable primacy, she's always put to the test to prove male soldiers she's worthy of her position, thus becoming a defensive character type.

Carter is a skilled agent, able to stand confrontations with her male colleagues, and a trained agent, who usually wields firearms in battle. She's got an incredible aim.

Relationships

 * Steve Rogers/Captain America - Ally and love interest.
 * Bucky Barnes - Ally.
 * Dum Dum Dugan - Ally.
 * Montgomery Falsworth - Ally.
 * Jim Morita - Ally.
 * Gabe Jones - Ally.
 * Howard Stark - Friend and ally.
 * Chester Phillips - Commander.
 * Sharon Carter - Niece.
 * Red Skull - Enemy.
 * Arnim Zola - Enemy.
 * Heinz Kruger - Enemy.

Appearances/Actresses

 * Marvel Cinematic Universe (5 films)
 * Captain America: The First Avenger (First appearance) - Hayley Atwell
 * Marvel One-Shot: Agent Carter - Hayley Atwell
 * The Avengers (Flashback only) - Hayley Atwell
 * Captain America: The Winter Soldier - Hayley Atwell
 * Avengers: Age of Ultron - Hayley Atwell
 * Marvel Cinematic Universe (1 TV series)
 * Agent Carter - Hayley Atwell
 * Marvel Cinematic Universe (1 comic)
 * Captain America: First Vengeance

Behind the scenes

 * Hayley Atwell based her performance as Peggy Carter on Ginger Rogers: "She can do everything Captain America can do, but backwards 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 where she encounters Steve in the present day, but it was ultimately cut from the final film by director Joss Whedon.
 * Hayley Atwell was aged using computer-generated imagery for her appearance as Old Peggy Carter, Anthony Russo commented that "all the old people have looked the same [in movies] since the 80s when you go down the make-up route." Joe Russo said: "We changed her face and her muscle structure and all of those things that change when you age".

Trivia

 * In the comics, Peggy is American. In the film, she's British. In real life, Atwell has a duel citizenship for the US and the UK.
 * In the movie Peggy works for the US Army, in the comics she fights with the French resistance.
 * In the comics, Peggy is the aunt of Sharon Carter, who partners up and develops a romantic relationship with Steve Rogers in the future.
 * In the comics, Peggy eventually dates Gabe Jones of the Howling Commandos.