The youngest of six Catholic brothers and sister, born to head teachers parents, Maggie grew up in the Midlands, where she was educated at a convent school, and after being inspired by a sixth-form drama teacher, "fell" into acting.
After training at the Guildhall School of Music and Drama, she starred in the video for Simple Red's Holding Back the Years, before making her professional stage debut in Moving Pictures, by Stephen Lowe, at the West Yorkshire Playhouse, Leeds in 1985. AFter making her screen debut in the British production Mona Lisa oppoite Bob Hoskins in 1986, she made her Hollywood screen debute in the Sigourney Weaver film Gorillas in the Mist: The Story of Dian Fossey in 1988. She also played alongside Keith Barron and Annette Crosby in the 1989 TV series Take Me Home.
Maggie played Dr. Alex Redman in ITV1's medical drama Peak Practice, but is best known to British audiences for playing Sheila Jackson on Channel 4's dramedy Shameless. Maggie has recently played Suzy Branning in the BBC1 soap operak, EastEnders.
Maggie lives in South London and enjoys pilates, yoga and reading.