In "Marvel's Agent Carter", which premiered in 2015, who played Agent Peggy Carter?

Hayley Atwell played Agent Peggy Carter in Marvel’s Agent Carter.

Atwell first portrayed Peggy Carter in Captain America: The First Avenger, released in 2011. She returned as the character in the 2013 Marvel One-Shot short film Agent Carter, which provided the direct starting point for the television series. Her performance established Carter as a capable intelligence operative rather than merely Captain America’s wartime love interest.

The ABC series premiered on January 6, 2015, and follows Carter after World War II as she works for the Strategic Scientific Reserve. While her male colleagues often push her toward routine administrative duties, she secretly investigates dangerous cases, including a conspiracy involving Howard Stark. James D’Arcy played Stark’s butler, Edwin Jarvis, who assists her in the first season.

The first season had eight episodes, and the show returned for a second season in 2016. Although it received positive critical attention, ABC canceled the series after two seasons. Atwell later reprised Peggy Carter in several other Marvel productions, including Avengers: Endgame and Doctor Strange in the Multiverse of Madness.