The daughter of actors Cyril Cusack and Maureen Cusack, she along with her two brothers and two sisters were raised in Dalkey, a seaside village south of Dublin, Ireland. She is an actress known for Hereafter (2010), In Love with Alma Cogan (2012) and Paris by Night (1988). She won a scholarship to the Royal Academy of Music in London where she studied the flute and performed professionally with the RTÉ Concert Orchestra and National Symphony Orchestra in Ireland before taking up acting and joining the Royal Shakespeare Company at 23. She came to more public prominence when she was cast in the popular television series Heartbeat (1992) as Dr Kate Rowan, leaving in 1995. She is married to the actor Finbar Lynch and have one son, Calam Lynch, who is also an actor.