Maura Tierney
 (Abby Lockhart)

A sharp medical student with an instinct for healing, Lockheart's residency is derailed when her deadbeat ex-husband fails to pay her tuition. To keep her job in the er, she falls back on her expertise as an intensive care/obstetrics nurse. Lockheart's life is further complicated by her ongoing recovery from alcoholism, her manic-depressive mother, and her relationships with both Dr. Kovac and Dr. Carter.

Maura Tierney joined the cast of ER as Abby Lockhart in 2000. She was born in Boston, Massachusetts, in 1965 and attended New York University and Circle in the Square Theatre, where she received her theatrical training. She has made notable TV appearances in The Van Dyke Show, Family Ties, NewsRadio and Law and Order. Her feature film career includes The Linguini Incident, White Sands, The Temp, Primal Fear, Liar Liar, Primary Colors, Forces of Nature, Scotland, PA, and Insomnia among her credits.