Karen is the daughter of recovering agoraphobic Sheila, Frank's second wife, and is famed across the Chatsworth Estate for her voracious sexual appetite and questionable taste. (She made the dubious decision to sleep with Frank while he was dating her mother and she was dating Frank's son Lip.)

The arrival of Jamie tames Karen's wild sexual ways and she eventually marries into his feared family, but only after enduring some severe psychological torture from Maguire matriarch Mimi.

Generous yet manipulative, Karen has a calculating side that helps her keep Jamie under the thumb (or so she thinks).

Every inch the reformed slapper, Karen makes the meteoric rise from barmaid at the Jockey to co-owner. The drama surrounding her pregnancy, her split from Jamie and her tumultuous relationship with Joe, however, ensures that life is rarely simple for her.