Atwell appeared in the BBC television adaptation of Alan Hollinghurst's novel "The Line of Beauty".

Atwell starred as Mary Crawford in "Mansfield Park" for ITV.

Atwell played Lucy in the remake of "The Prisoner".

Atwell starred as Freya Deverell in "Any Human Heart", a mini-series based on William Boyd's novel.

Atwell starred as Consuelo Jimenez in "Falcon".

Atwell starred as Martha in the "Black Mirror" episode 'Be Right Back', receiving critical acclaim.

Atwell starred as Peggy Carter in "Agent Carter", a spin-off series from the "Captain America" films. The show ran for two seasons on ABC.

Atwell played Hayes Morrison in the legal drama "Conviction", which ran for one season on ABC.

Atwell starred as Margaret Schlegel in the BBC and Starz adaptation of E.M. Forster's "Howards End".

Atwell appeared in an episode of "Criminal: UK".

Atwell reprised her role as Aliena from Pillars of the Earth.

Atwell voiced Peggy Carter/Captain Carter in the animated series "What If...?", exploring alternate scenarios in the Marvel Cinematic Universe.

Atwell played Jonathan Wilde in Apple TV+ "The Completely Made-Up Adventures of Dick Turpin"