Abby Lockhart is one of the most intricately drawn characters to grace the E.R. cast and is portrayed to perfection by Maura Tierney. She makes her first appearance in season 6 as the OB nurse that oversees the birth of Carol Hathaway's twin girls. She returns several episodes later when we learn that she is a med student beginning her ER rotation ("What can I say? I've gone over to the dark side"). As a med student she is she interacts well with all of the personnel and creates a persona of an eager yet less-than-confident doctor-in-training. It is Abby that sees Carter abusing medication and begins the process that sends him to rehab at the end of the season. When season 7 begins, we learn that Abby is an alcoholic herself when Dr. Carter runs into her at an AA meeting. We also learn that she is recently-divorced. She is forced to drop out of med school when her physician ex-husband stops paying her med school bills because of a "tax issue." Kerry Weaver brings her from OB to the ER as a nurse - "where she will see more medicine if she plans to return to med school." She begins a relationship with Dr. Luka Kovac (albeit a violent beginning when he accidently kills a mugger who was threatening her) and continues to dally in friendship with Carter. Abby's distorted childhood is fleshed out as we are introduced to her bipolar Mom (exquisitely protrayed by Sally Field). Torn about how to handle her mother's relapse into depression, Abby chooses to bring her back to Chicago; she is aided on this road trip by Carter, much to Luka's chagrin. Abby is distrustful of her mother's recovery, and her resolve to stay on her medication, yet she shares the tortured memory of a secret abortion during her marriage to Richard. Maggie is encouraging and tells her to stop sitting on life's sidelines, to stop blaming herself and to go after what she wants.
As her friendship with John Carter deepens, she is pulled away from Luka. They have a horrendous fight that results in a break-up. Theirs is a thread that is hard to break however. After Abby is assaulted by a neighbor's husband, Luka finds him in a local bar, beats him up and threatens to kill him if he ever goes near her again. The 'triangle' between the two men competeing for her affection is played out in a season 8 episode, "Secrets and Lies." In that episode we learn that Abby is a graduate of Penn State, with a minor in English, and likes being a nurse despite the contempt she thinks doctors have for those "under" them. As season 8 ends, Abby and Carter are victims of a lockdown in the ER due to their exposure to a patient with infectious monkey pox. Their relationship heats up, and speeds ahead throughout season 9. In the background is an even more tortured Dr. Kovac as he watches them grow closer. We are introduced to Abby's younger brother, Eric, who is eventually also diagnosed with a bipolar condition. He eventually seeks refuge with his mother, much to Abby's chagrin.
Unable to get a grip on his own life, and Abby's relationship with Carter, Luka heads off to the Congo with a Doctors Without Borders-type of organization. Carter very nearly proposes to her, and yet is unable to acquiesce to her need to put her family's needs before her own...and his. He soon joins Luka in Africa. Abby is devastated, and refuses to allow Carter back into her life when he returns. She is even more devastated when it appears that Luka has been killed in Africa. Carter goes to Africe and finds Luka, nearly death; and Luka is returned to Chicago-- without Carter. Abby is relieved at Luka's return, and begins to make empowering choices for herself. She returns to med school. She basks in her friendship with Luka. She is a bit taken aback when Carter returns, with a partner who is pregnant with his child, yet accepts that they were not meant to be. She becomes a well-respected and astute intern and resident. While those around her know that she has "that special something" that makes her a good doctor, Abby still lacks confidence in herself.
Season 12 finds her back with Luka romantically, and then pregnant with his child. Struggling with the ifs about what they really mean to one another this time, she decides to have the baby...and a relationship with Luka. At last, it seems as if all her demons are at bay and she will have the life she has always wanted.
As season 12 ends and season 13 begins, Abby is caught in the middle of a gun fight at the E.R. corral and her child's life is in danger. A premature birth, hysterectomy and infant needing surgery bring Luka and Abby closer than ever...and into a world of happiness as they become a family. The depth of her feelings for Luka come hitting home as she is threatened and held hostage by an angry ex-patient. As they wait for an unsuspecting Luka, Abby reveals to Curtis Ames that she was once so deeply entrenched in alcohol that she suffered a blackout, but was able to turn her life around. Although she is unsure of all the "trappings" of a wedding and formal marriage, Luka convinces her to marry him in a secretly planned wedding. Interestingly enough it was perfectly in synch with everything he knows about her.
Barely a week after the wedding, Luka is called back to Croatia for his father's illness. The "quick trip" turns into 6 months and Abby is left alone with her work and the baby. Probably borne out of the frustration of being alone for so long, Abby relapses into alcoholism. She suffers another blackout and finds herself in the bed of the new ER chief, Kevin Moretti. Horrified, her first thoughts are to get to Luka. She gathers up the baby and heads for the airport. Thwarted by security, she stays home and continues to secretly drink.
Luka returns and senses that something is wrong. She asks for his help and admits herself into rehab. When she is out, she joins him in Croatia and tells him about the night with Moretti. Upon returning to Chicago, Luka moves out and Abby is left wondering if she has lost everything in her personal life. As she faces the end of her formal education as a doctor, she begins to achieve her goals professionally--she is named an Attending in the ER where she began as a nurse. And then Luka makes a decision of his own. He does not want to live without her by his side. They have something altogether too precious to lose. Stunned - and thrilled - that it has turned out this way, Abby makes a decision to put her family first. At Luka's request they will leave Chicago - together - for a fresh start somewhere else.