John-Kamen began her career in 2011, providing voice work for the video game
Dark Souls. She went on to make appearances in episodes of television series
Misfits (2011),
Black Mirror (2016),
Whitechapel (2012),
The Syndicate (2012),
The Midnight Beast (2012) and
The Hour (2012). From 11 December 2012 to 29 June 2013, she took the lead role of Viva in the
Spice Girls-themed
West End musical
Viva Forever! The musical premiered at the
Piccadilly Theatre to largely negative reviews. In 2015, John-Kamen had a starring role in the
SyFy series
Killjoys. In 2016, she had a guest-star role on the
HBO series
Game of Thrones. That year, she appeared in the
Black Mirror episode "
Playtest" and an episode of
The Tunnel. Addressing John-Kamen's role in
Steven Spielberg's
Ready Player One (2018), Kristen Tauer wrote, "While much of
Ready Player One takes place in a virtual reality world, Hannah John-Kamen's character is unique in that she is rooted in the reality throughout the film." That same year, John-Kamen played
Ava Starr / Ghost in the superhero film
Ant-Man and the Wasp. In 2021, John-Kamen starred in the action-thriller film
SAS: Red Notice and portrayed
Jill Valentine in the reboot film
Resident Evil: Welcome to Raccoon City. She was cast as
Red Sonja in the upcoming film by the same name from Millennium Films but reportedly left the project for unknown reasons. In 2023, John-Kamen starred in the
folk horror film
Unwelcome alongside
Douglas Booth. In 2025, John-Kamen reprised her role as Ava Starr / Ghost in
Thunderbolts* (2025), and it was announced that same year that she would also reprise the role in
Avengers: Doomsday (2026). == Personal life ==