Peggy’s niece, Sharon Carter, idolized her aunt, enthralled by stories of the war and romance with Captain America. Peggy proved to be a greater influence on her niece than the youth’s own parents, something Sharon’s father never forgave his sister for, especially after the younger Carter joined elite intelligence agency S.H.I.E.L.D. Sharon was trying to emulate her aunt’s past as a woman of action, and she also hoped working with S.H.I.E.L.D. might lead to partnering with Captain America, who had then-recently revived from suspended animation.
Taking the codename Agent 13 in her aunt’s honor, Sharon teamed with Cap on several S.H.I.E.L.D. missions and they fell in love, partly because of the woman’s remarkable resemblance to a younger Peggy, though the hero was unaware the two were related. Feeling disloyal to Peggy because of this, Sharon repeatedly refused Cap’s marriage proposals and eventually tried to end their romance.
Meanwhile, Peggy had sunk into another period of depression and amnesia, and Sharon’s parents placed her in the Lost Souls Asylum & Rest Home, run by corrupt psychiatrist Dr. Faustus and his associate Dr. Johann Wolfgang. An old foe of Cap’s, Faustus had arranged to treat Peggy in hopes she might give him unique inside information about his rival’s psyche.
When Captain America, his partner Falcon (Sam Wilson) and Sharon all investigated the asylum, Faustus forced them to participate in his re-creation of Peggy’s final wartime battle, which shocked Carter back to a state of mental clarity. However, Peggy soon realized how her doctors were manipulating her, and she helped Cap and the others defeat Faustus and Wolfgang. Cap and Carter were reunited, and the former finally learned how Sharon and Peggy were related.
Cap resumed his romance with Sharon, but they initially concealed this from Peggy, not wanting to set back her mental recovery. Her memories of the decades since World War II hazy at first, Peggy had difficulty accepting how much she had aged, assuming her romance with the costumed hero could simply pick up where it left off.
Still remarkably fit despite her advanced age, Peggy worked with S.H.I.E.L.D. to refresh her old wartime skills and be closer to Captain America. Assigned as backup to senior S.H.I.E.L.D. agent and fellow WWII veteran Gabe Jones during his second infiltration of the subversive Secret Empire, Peggy helped her colleague—along with Cap, Falcon and the X-Men—thwart the evil organization’s attempted overthrow of the US government. When the exposure of a high US official as the Empire’s leader drove a disillusioned Captain America into retirement, Peggy tried in vain to talk him out of it. Shortly thereafter, Cap finally told Peggy as firmly as he could that their romance was a thing of the past. Heartbroken at first, Peggy found comfort in her increasingly close friendship with Gabe Jones, which was gradually becoming romantic.