DR. JOHN CARTER
(Noah Wyle)

Resident: Now a senior resident, Dr. John Carter is experiencing all the joys and trials of his first years as a doctor. His three years in the emergency room plus a year as a surgical intern under the intense scrutiny of Dr. Benton have prepared him well, but some lessons can only be learned through experience.After a violent attack by a patient left a medical student dead and seriously wounded him, Dr. Carter succumbed to substance abuse. Since his cousin was disabled by a drug overdose, Dr. Carter was very motivated in his own recovery. With his parents' recent separation, Carter often turns to his grandmother for strength in tough times. After his brief flirtation with Susan Lewis ended, Carter close friendship with Abby deepened into love.

DR. KERRY WEAVER
(Laura Innes)

Chief of Emergency Medicine: Dr. Weaver first came to County General as chief resident, later becoming attending physician in the ER. In her current job, the direct, abrasive Dr. Weaver remains undaunted by her physical disability that requires her to walk with a crutch. Dr. Weaver is a highly talented physician with less-than-gracious social skills and a penchant for over-management. But her unmatched abilities in critical situations have earned her colleagues' respect, if not their affection. Just recently, Dr. Weaver's social life took an upturn when she came out as a lesbian. She also continues her secret search for her biological mother.

DR. ELIZABETH CORDAY
(Alex Kingston)

Associate Chief of Surgery: Dr. Elizabeth Corday is a gifted British surgeon who has come to the States to gain experience in the violent traumas unique to an urban American emergency room. Dr. Corday juggled her demanding career with a new marriage to Dr. Greene and a new baby. Corday was sad to see fellow surgeon (and ex-boyfriend) Dr. Benton leave the ER, mainly because it left her alone to battle the antagonistic chief of staff, Dr. Romano. When Dr. Greene's daughter, Rachel, endangered the life of their new baby, Dr. Corday chose to move out. After the return of Dr. Greene's cancer and his subsquent death. Dr. Corday has to cope with being a widowed surgeon and mother.

DR. LUKA KOVAC
(Goran Visnjic)

Attending ER Physician: A sexy Croatian doctor who began his career at Country General by moonlighting, Kovac soon earned a full-time position in the er. Having lost his family in his war-torn homeland, Kovac came to America for a fresh start and to get away from his painful past. Kovac often gets overly involved in his patients' cases, which causes friction between him and the chief of emergency medicine, Dr. Kerry Weaver. Now a year out from his unhappy relationship with Abby, Luka is enjoying a bachelor lifestyle.

ABBY LOCKHART
(Maura Tierney)

Intensive Care Unit Nurse: A sharp medical student with an instinct for healing, Lockhart'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. Lockhart'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.

DR. JING-MEI CHEN
(Ming-Na Wen)

Resident: Previously known as Deb Chen, Jing-Mei was a former County General medical student who quit medicine and recently returned. Dr. Chen is a physician who's sacrificed everything for her career. Recently fired for a misdiagnosis that resulted in a patient's death, Chen returned when she was able to prove Dr. Weaver's negligence in the case. Their relationship remains awkward at best. Dr. Chen also gave birth to an interracial baby, alienating her from her strict, traditional family. She gave the child up for adoption.

DR. ROBERT "ROCKET" ROMANO
(Paul McCrane)

Chief of Staff: A familiar face around County General the aptly nicknamed chief of staff "Rocket" Romano is a highly skilled -- and highly volatile -- surgeon whose abrasive and duplicitous nature causes problems for the docs of County General. Although his ego knows no bounds, deep-down Romano cares intensely about his work and respects those who will stand up to him.

DR. SUSAN LEWIS
(Sherry Stringfield)

Resident: Tough, talented medical resident Dr. Susan Lewis has sacrificed nearly everything to pursue her medical career. Saddled with her drug addict sister's baby (little Susie), she grows to love the little girl and plans on keeping her, only to lose her when the court returns custody to her sister. The pressures of balancing the demands of the E.R., her overbearing family's expectations and her own driving ambition finally prove more than she chooses to deal with and she departs for Phoenix to be close to her sister and Susie. But fate brings her back to the E.R. five years later. Upon her return, she met with some resistance from Dr. Weaver, but has slowly eased back into the familiar surroundings. ER gossip has always had her romantically involved with Dr. Greene, but they were only just friends.

MICHAEL GALLANT
(Sharif Atkins)
Medical Student: Michael Gallant is a fourth-year medical student who is working his way through medical school on the U.S. Army’s ticket.
 

DR. GREGORY PRATT
(Mekhi Phifer)
Pratt is an arrogant intern whose over-confident tendency to do first, and ask permission later further agitates the already chaotic ER.