[2] After training at Rose Bruford College, Fergison started playing the role of Heather Trott on the BBC soap opera EastEnders on 26 June 2007.

Fergison also starred in a promotional video for the band Keane's single "Atlantic", which was included on their Under the Iron Sea DVD.

On 17 September 2011, Fergison was axed from EastEnders and it was announced that she would leave at the end of her current contract, departing the show on 21 March 2012.

[8] During the series, she sang as Dusty Springfield, Anastacia, Meatloaf, Lulu, Madonna, Cher and Adele.

[10] The recording was a taped message left by Heather for Dot Branning (June Brown), who discovered it on her last day working in the launderette.

[10][11] From October to November 2018, she played the part of Mrs Bird in the musical production of Maggie May at the Royal Court Theatre in Liverpool.

[12] In 2022, she played a fictionalised version of herself in Catherine Tate's six-part mockumentary sitcom Hard Cell, released on Netflix.