Wakefield was born 18 September 1980 in Sussex, England. At a couple of months old she moved with her mother Caroline to Villajoyosa, a small village near Alicante in Comunidad Valenciana, Spain. They returned to East Sussex, England, when Wakefield was four. She has a seven years younger half-sister, Olivia. Her maternal grandfather was actor James Hayter.

Wakefield went to Bexhill College, and studied acting at the Oxford School of Drama from 2000 to 2003. As well as acting, she plays the violin and has a strong Soprano singing voice.

Wakefield made her screen debut in 2004, in (Past Present Future) Imperfect. She starred in a BBC1 production of Rapunzel, in which Rapunzel is a young tennis star, and also appeared in Casualty 1907.

Her theatre credits include Yesterday Was a Weird Day, a production about the 2005 London bombings, Constance in The Three Musketeers at the Bristol Old Vic, and Elaine in The Graduate, at the New Vic. Wakefield's performance as Susan in Baby with the Bathwater at the Old Red Lion Theatre was called "fabulous."

In 2008 she toured in a revival of W. Somerset Maugham's The Circle at the Chichester Festival Theatre, as well as working on the BBC comedy pilot Freddi. She appeared in the Channel 4 drama Any Human Heart and played the lead in the British film noir Scar Tissue. In March 2012 she was cast in Mockingbird Lane, the re-imagining of The Munsters for NBC.

She recently appeared as Mary Boleyn in the 2015 BBC2 television series Wolf Hall. She also appeared in the NBC drama The Player with Philip Winchester and Wesley Snipes.

In January 2017, she appeared in the ITV drama The Halcyon, playing Charity Lambert.