Kelly's subsequent television roles include Lady Mae in Mr Selfridge (2013–2014, 2016), DI Jodie Shackleton in Happy Valley (2016), Miss Andrea Quill in Class (2016), Jane Lowry in Strike Back (2017–2018), DCI Natalie Hobbs in Criminal: UK (2019–2020), Elizabeth Sutherland in Gentleman Jack (2019–2022), DI Karen Renton in Liar (2020), Sally Wright in Innocent (2021), and Angela van Den Bogerd in Mr Bates vs The Post Office (2024).

She has strong links with The Lamproom Theatre in Barnsley, established in 1998 by her father John (who is originally from Castleisland, County Kerry, Ireland), and has regularly supported fund-raising events held there.

[2][3] She trained at the Royal Academy of Dramatic Art with fellow students Meredith MacNeill,[2][4] Leo Bill,[5] Elliot Cowan,[5] Laurence Fox,[2][4] and actor/novelist, Anna Hope,[5] graduating in 2001.

Kelly, in character as Becky McDonald, sang the lead single from the album, If It's Too Late, which was remixed by former PWL and Stock Aitken Waterman "Mixmaster", Pete Hammond.

[8] Kelly's first television role after leaving Coronation Street was in the 90-minute BBC Four biopic The Best Possible Taste, in which she played Lee Middleton, wife of Kenny Everett.

Kelly enjoyed the opportunity to play a character in her native Yorkshire accent, and prepared for the role by shadowing police detectives in Halifax.

The following year, Kelly appeared in the feature film Official Secrets, based on the real life events of intelligence whistleblower Katharine Gun (portrayed by Keira Knightley).

In the film, Kelly plays Jacqueline Jones, an MI6 agent who tacitly confirms the legitimacy of Gun's leaked memo to a journalist contact at The Observer.