Johnson attended Highgate Wood School and Performing Arts College where she was spotted by an agent in a production of Guys and Dolls in which she played the lead.
The role of Vicki Fowler on the BBC's flagship soap opera EastEnders was Johnson's first television role though not her professional début, having previously appeared in numerous stage productions, including a six-month run in an acclaimed National Theatre production of Dylan Thomas' Under Milk Wood directed by Roger Michell. Johnson l