Career as a doctor
In 2003, Abby starts her final year of medical school and newcomer Samantha Taggart replaces her as the central nurse character on the show. As both a nurse and later a doctor, Abby has a tendency for sarcasm towards troublesome patients (and her co-workers), but she exudes gentleness and security as well. Although she is not as intellectually gifted as Neela Rasgotra, John Carter or Gregg Pratt, she has many years of experience and one of the highest patient-satisfaction scores. It is a mark of Kerry Weaver's confidence in Abby that, when she has her hip-replacement surgery in Season 12, she asks Abby to be her son Henry's legal guardian if something happens to her. Towards the end of her final quarter of medical school, she is told that someone has anonymously paid off the balance on her tuition. She later discovers it was Carter. Abby goes on to graduate from medical school and finally becomes Dr. Abby Lockhart. By season 14, Abby is a fourth year resident. She applies for an Attending position at County when she becomes frustrated by the endless delays and interviews for a position at an upscale medical facility, although this is partly because she wants to keep her options open if Luka decides to reconcile with her. She gets the other position, but Dr. Pratt uses his pull to get County to offer her the Attending position, which she accepts, one episode before Luka decides to forgive her.
After leaving with Luka to work in Boston, Abby appears once more in season 15 episode 20, "Shifting Equilibrium", during a phone call with Neela, who needs Abby's encouragement to leave County. Abby is seen in her new home looking after a group of young children for her after-shift daycare, including a three-year-old Joe.