She is known for her roles as Tina McIntyre in the ITV soap opera Coronation Street (2008–2014) and Georgie Lane in the BBC military drama Our Girl (2016–2020).

Keegan has also starred as Tina Moore in the biopic Tina and Bobby (2017), Erin Croft in Sky Max comedy Brassic (2019–present), Kate Thorne in BBC period drama Ten Pound Poms (2023–present) and Maya Stern in Netflix thriller Fool Me Once (2024).

[14] Keegan made a guest appearance as herself in the 2009 Easter special Red Dwarf: Back to Earth.

[15][better source needed] In 2015, she was cast as Tracy Shawcross in the BBC television drama series Ordinary Lies.

[21] Keegan portrayed the main character, Erin Croft, in Sky One's comedy-drama series, Brassic, which started in 2019.

[22][23] On 22 February 2022, Keegan was a guest judge on the Snatch Game episode of the first series of RuPaul's Drag Race: UK vs. the World.

[25] Keegan starred as the main character, Maya Stern, in the 2024 eight-part television series Fool Me Once, adapted from the 2016 Harlan Coben novel of the same name by Danny Brocklehurst and made for Netflix by Quay Street Production.