The 15 Best Characters That ‘ER’ Introduced Over 15 Seasons

Before Grey’s Anatomy broke its record in February 2019, ER was the record-holder for the longest American prime-time network medical drama, at 15 seasons and 331 episodes. Considering it premiered in 1993, the series was remarkably ahead of its time in many respects, which is likely how it managed to last as long as it did. For a decade and a half, the halls of Chicago’s County General Hospital saw countless faces come and go in triumph, tragedy, and everything in between, and so in honor of those fifteen seasons, we present the top fifteen ER characters.

Editor's Note: This article contains spoilers for all fifteen seasons of ER.

The 15 Best Characters That ER Introduced Over 15 Seasons

15. Jerry Markovic


Every procedural needs their comic relief to keep them from getting bogged down in the drama, and for ER, that person was Jerry Markovic (Abraham Benrubi). One of a series of rotating desk clerks at County General, Jerry stood out as being the sweet and considerate one, even if he did have his moments of cluelessness or naivete that caused complications—though never on the scale of the medical emergencies that came through the hospital.

Jerry was a mainstay for the first five seasons, returning midway through the show’s run for an additional 5 seasons, then inexplicably disappearing again until the series finale. Despite this, he still ranks among the top characters on the series purely for the levity he brings when the series needed it the most, and never in a way that sets your teeth on edge. True, he didn’t have a character arc in the traditional sense, but he was always such a sweet, welcome presence and deserves a spot on this list for that reason alone.

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14. Dr. Robert Romano

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No one in their right mind would call Robert Romano (Paul McCrane) a good person. The man is any kind of toxic you can think of and discriminatory to a fault. Yet he ranks on this list purely because he is the closest thing ER had to a human antagonist, as opposed to the concept of an overburdened, underfunded, unjust healthcare system, which is arguably the primary villain of the series.

When he first appears in the fourth season, Robert is, to put it bluntly, an abrasive asshole. He says cruel things to his colleagues and to patients, and when in doubt he always takes the least popular solution to a problem. But he is good at his job, and therefore is allowed to remain in a position of authority with little more than a slap on the wrist for each infraction. It is infuriating to watch, more so because the audience knows that these kinds of things happen in every profession every day.

There are just enough shades of grey and moments of vulnerability for him that stop him from being a one-dimensional baddie. Though these moments of humanity and kindness are buried under several layers of bitterness, by the time he is killed in the tenth season—crushed by the same helicopter that severed his arm the season before, which is exactly as wild as it sounds—you almost feel bad that the man goes largely unmourned except by a select few hospital employees.

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13. Dr. Doug Ross

It’s not an ER ranking without mentioning County General’s original good-looking bad boy Dr. Doug Ross (George Clooney). Everything about him was designed to make you weak in the knees. He’s athletic and charming. He has an “I can fix him” womanizer vibe, until he finally admits he’s in love with Nurse Carol Hathaway (Julianna Margulies). He specializes in pediatric medicine, so he’s good with kids. And the fact that he’s played by George Clooney certainly doesn’t hurt either.

Like the other doctors in the early seasons, Doug also takes a very strong stance against the injustices of the health care system. He establishes an emergency pediatric clinic for those who cannot afford care otherwise. It’s ultimately the lengths he goes to do the best for his patients that gets him in trouble more often than not, which led to his character taking a job in Seattle at the end of the fifth season. He returned to the series twice after his departure. Once for a surprise (and swoon-worthy) reunion with Carol, and once in the final season for a highly publicized, albeit bittersweet episode.

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12. Haleh Adams

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The nursing staff is the backbone of the hospital, and Haleh Adams (Yvette Freeman) is the backbone of the nursing staff. Though she doesn’t care much for the management side of things, preferring to work directly with patients rather than drown in administration and paperwork, it’s clear to anyone watching that both the doctors and the nurses defer to Haleh’s judgment.

For all fifteen seasons of ER’s run, Haleh is a constant presence at the hospital. In such a sprawling cast, she is one of only six characters to appear in every season. However, even though she is there to watch doctors and nurses come and go, she doesn’t have much of a character arc to call her own. She is the face of the struggles that nurses face every day, from being undermined to being overworked and taken for granted. If the doctors of ER advocate for better healthcare for patients, it is Haleh who advocates for better treatment of those who spend their lives providing that ongoing healthcare and personal touch.

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11. Dr. Abby Lockhart

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A main character on a network drama getting to be messy in the way real people are every day is a privilege usually reserved for men. But of all the characters to walk the halls of County General’s emergency department, Dr. Abby Lockhart (Maura Tierney) is probably the messiest. And we love her for it.

Initially introduced as a nurse in the maternity ward, Abby later transfers to the ER where she works to offset the costs of her and her ex-husband’s medical school bills. Once there, her struggles become more and more apparent. A difficult, inconsistent upbringing paired with her own struggles with addiction and the stigma attached to that mean that Abby is emotionally closed-off. Small progress is often set back as her past comes back to haunt her and make her shut down. This sets her in some contrast to the two men who are romantically interested in her, as both of them are very affectionate and emotionally available.

Another series might have written her out or changed her drastically from season to season. But in her ten seasons on the show, Abby is given room to grow and to slowly open up to those around her, finding not only a healthy romantic relationship, but several close friendships along the way. Watching everything she’s had to overcome makes her eventual success in completing medical school that much more cathartic.

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10. Dr. Susan Lewis

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ER — Season 1 — Pictured: Sherry Stringfield as Dr. Susan Lewis — Photo by: NBCU Photo Bank

If County General had a resident party girl, it was Dr. Susan Lewis (Sherry Stringfield). When the series premiered, she was one of two female leads, and was the only female doctor among the main cast. For the first two and a half seasons, it seemed like the writers were unsure what to do with her. They eventually introduced some family drama in the form of her younger, troubled sister Chloe who leaves Susan with her baby daughter then leaves town completely. She was also one half of a will-they-won’t-they (they didn’t) with her closest ER friend, Dr. Greene. All this to say with so much of her story hanging on her being all things to all people, it’s little wonder she left after two and a half seasons.

When she returned to the show in the eighth season, it was to a vastly different hospital and a whole new sea of faces. But the five years away brought in a much-needed shift in character for Susan. Her dry, sarcastic humor made her feel a little offbeat from the others at the hospital. She was able to embrace her fun, flirty side and be more exuberant than she was in the beginning, and her time away proved to be a breath of fresh air both for the character and for the audience.

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9. Dr. Jing-mei “Deb” Chen

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To say it’s not easy being a doctor is one heck of an understatement, but it’s something ER really drove home, particularly in the early seasons. Take Dr. Jing-Mei Chen (Ming-Na Wen) who first made a few guest appearances in season one as a nervous, very keen medical student. At the end of her first arc, she leaves the hospital claiming medicine isn’t for her as she prefers the science of it to the actual patient care.

Despite this assertion, she returns in the sixth season as a much more confident, licensed doctor. The audience learns that both her parents are successful doctors, contributing in part to why she chose medicine as a profession. There is something refreshing in seeing a character take on that kind of familial pressure so many of us are familiar with and making it their own. She doesn’t rebel by choosing a different path, she just makes the best of the one she is on. Much like Susan Lewis, Jing-Mei is also one of the more fun-loving doctors in the ER. She likes casual relationships and never lets any of them set the terms for her life and her enjoyment, though of course she has her moments of vulnerability and introspection.

Sadly, her character suffers overall in the ranking due to the abrupt way she left the show. After losing both of her parents in quick succession, she takes a leave of absence, unsure when she’ll return, and ultimately never does, making her one of the few main characters to not appear in the final season.

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8. Dr. Mark Greene

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A consistent presence for the first eight seasons, Dr. Mark Greene (Anthony Edwards) is the glue that holds the emergency department together. He is the rock-solid foundation on which the entire series was built. Despite a contentious relationship with his ex-wife, he does his best to never bring that to work with him. He is an unfailingly patient father to his daughter Rachel, even as she becomes increasingly bratty and hard to watch as a viewer.

He is a consummate professional and an ideal boss. The kind where his voice hardly ever raises, and the kind that will always have the back of those who work under him. He is a good friend, and mentors the more junior doctors. In short, there wasn’t really anywhere for him to go. You can only give him so many professional entanglements before you start questioning his ability as a doctor.

Because Mark is so unshakeable, it took a tragedy of epic proportions to add stakes to his story. Shortly around the birth of his second child, with Dr. Elizabeth Corday (Alex Kingston), Mark learns he has a brain tumor that is slowly killing him. The audience sees it coming, and we get a whole episode to say goodbye, but that doesn’t make it any easier.

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7. Dr. Greg Pratt

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Something that tends to happen with long-running ensemble pieces is the minute someone new shows up, the dynamic changes. By the time Dr. Greg Pratt (Mekhi Phifer) shows up in the eighth season, even the newer cast members have settled into the routine of County General, and then in arrives this student who believes he knows more about the practice of medicine than the professionals he is meant to be learning from.

Greg’s growth between the eighth and fourteenth seasons is among the strongest on the series. Even though he repeatedly expresses the desire to leave County in favor of a better-funded hospital, the rush of it all—and yes, the relationships he fosters—always wind up pulling him back. It’s one of the great disappointments of the series that his quasi-romance with Jing-Mei Chen never gets a satisfying resolution, even though Greg was there for her through the loss of her parents, and their chemistry was fantastic.

On a much sadder note, though many will cite Mark Greene’s death as the saddest on the series, we feel that that distinction should arguably go to Greg Pratt. While Mark had time to come to terms with it and say goodbye to his family, Greg’s death was unexpected. Phifer’s performance sees him cycling through the five stages of grief in a matter of seconds while on the operating table, and came as a real shock. A devastating end for the character we had all come to love.

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6. Dr. Neela Rasgotra

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One of the things that makes Dr. Neela Rasgotra (Parminder Nagra) such a great character is how relatable she is. Few characters on ER are ever seen questioning the decisions they made to pursue medicine, even though it is constantly shown to be a physically and emotionally demanding pursuit. Neela is the first time the audience ever sees one of the characters fully cracking under the pressure.

When given the opportunity to work at the University of Michigan hospital after graduation, Neela panics and leaves, taking a job as a cashier at the general store across the street from County General. While she eventually makes it back to County, and eventually goes on to become a surgeon there, it's that moment of doubt and questioning your entire field of study that strikes such a cord, especially with audiences now.

Neela’s relatability extends to her romantic life too. She is just as indecisive with the men in her life as she is with her career. As ideal a concept as “one true love” is, the reality is often having to choose between two or three fine-if-flawed choices, which is where Neela finds herself until her arc comes full circle in the final season. By then, she is a far more confident individual, more at ease in her decisions.

Parminder Nagra has great comedic timing and through her Neela’s sense of humor really shines through material that might otherwise be very dramatic, or over the top, as parts of the last few seasons certainly were.

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5. Carol Hathaway

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The sheer power of Julianna Margulies cannot be understated. She took Carol Hathaway, a nurse who was supposed to die in the pilot episode, thereby providing an emotional catalyst for the rest of the ER crew, and infused her with such a sweet, determined spirit that the showrunners decided to recut the episode to leave her fate ambiguous.

A notable thing about ER as a whole is the way in which it addresses systemic inequalities when it comes to the health care people receive. When proper care becomes increasingly inaccessible to the patients of County, Carol is the one who obtained private funding to run a pro bono clinic out of the ER and run it in addition to her other duties.

After surviving her attempted fridging, Carol went on to become the heart of the Emergency department for the first six seasons of the show. Margulies performance is infectious (no terrible medical pun intended). Carol is vulnerable without ever seeming passive, she is good at her job and proud of what she does, and she is never afraid to seize agency for herself and those in her care.

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4. Dr. John Carter

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Though ER is an ensemble show, if anyone was a point-of-view character for the audience in the early seasons, it was Dr. John Carter (Noah Wyle). He initially started his run at County as a medical student on his Emergency rotation, and as he grew accustomed to the inconsistent resources and grueling schedule, so too did the audience.

As the son of an ultra-rich family, medicine is seen as a suitable pastime until he assumes his real role as head of the family foundation. But it’s more than that for him. John genuinely cares about his patients, and wants to be the best doctor he can be, switching out of surgery and redoing his first year of residency with no pay just so he can be in Emergency where his real talent lies.

John is consistently forced to reckon with the privilege he grew up with that does not extend to those he treats. After a quick volunteer stint in Congo with Doctors Without Borders, he becomes frustrated with the bureaucracy of County General and begins making longer, more frequent trips to African countries in need of medical care. When he does eventually return to the States, it is to use his family money to build an HIV/AIDS hospital close to County.

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3. Dr. Peter Benton

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The superstar surgical hotshot of the Emergency Department, Dr. Peter Benton (Eriq LaSalle) isn’t easy to like at first. But he’s not there to be likable, he’s there to do his job. While the almost single-minded determination to perform and perform well makes him hard to read at first. But at his core, Peter is a kind man with a lot of love to give. Sure, he can be abrupt and doesn’t always excel at reading the room, but he is always there when it matters, for both his family and his colleagues.

As the only Black man among the main cast until Sharif Atkins arrived in the eighth season, LaSalle was very aware of what his character represented to the audience. It was at his request that his character's relationship with Elizabeth Corday was terminated, because he disliked that the only emotionally stable relationship his character had been in thus far was with a white woman.

His most significant non-romantic adult relationship, with his one-time student John Carter, is honestly one of the great TV friendships. Despite treating him harshly at first—because surgery is a very sink-or-swim pursuit—it's obvious to anyone watching that he truly does love John and value him as a friend, or even a younger brother. When he unexpectedly becomes a father, and then very quickly a single father tied up in a messy custody battle, it’s then that his heart and his priorities really come roaring to the surface.

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2. Dr. Kerry Weaver

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Before Dr. Romano became the primary antagonist to the ER staff, that dubious honor went to Dr. Kerry Weaver (Laura Innes). Initially brought on as the chief resident, she rose quickly in the ranks, all the way up to hospital administration. Because she is an ambitious woman, this often puts her at odds with the rest of the staff, who resented her “my way or the highway” approach to things.

Over the course of her twelve seasons, however, Kerry became most like someone you might actually work with. Not all good, not all bad, a little tough to read sometimes. Her decisions weren’t always the popular one—and she certainly didn’t mind being the one to make a tough call—but they were always made in an attempt to placate as many people as possible.

Oftentimes when Kerry is mentioned by those who have seen the show, two points come up. Namely that she is a queer woman, and a woman with a physical disability. These are especially noteworthy considering when the show came out, and the length of time Kerry appeared. Granted, it was the late 90’s and early 00’s, and not everything holds up today. The same can be said for a lot of the progressive angles ER took. But the fact that it happened at all, and with such a prominent character, can’t go ignored.

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1. Dr. Luka Kovac

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Long before Roy Kent and Nick Miller graced our screens with “man written by a woman” energy, there was Dr. Luka Kovac (Goran Visnjic). Tall, handsome, and broody, with a tragic backstory and a heart of gold, Luka exhibits the kind of open affection and understanding usually reserved for a man in a romance novel.

He moved to Chicago from Croatia after losing his wife and children in the War of Independence, and channels his grief into his work. When faced with the same frustrations and limitations of the health care system seen throughout the series, he opts to take extended leaves of absence to volunteer with Doctors Without Borders. He can recite Hamlet off the top of his head in Croatian, which is apropos of nothing, but is very hot of him.

Initially brought in to fill the bad boy gap left behind by George Clooney’s departure, Visnjic not only understood the assignment but ran wild with it. Luka has an air of mystery but never menace. He is open and unashamed of his emotions and affections. He is protective of those he loves, and trusts people to do the right thing. He never lets his personal beliefs affect the way he provides care to his patients. Though he still carries the pain of his loss, it doesn’t stop him from being there for friends in need and from opening himself up to love again.

Because Luka is also a romantic. The worst thing that can be said about him is that he is determined to help people, whether or not that help is wanted. It’s this pressure to let him fix things that causes his initial break-up with Abby. Ultimately, it works out for the best, since the two of them then get to find their way back to each other with a delicious slow-burn romance.

A good man, good partner, good father, and good friend, wrapped in a dark and broody package. By far the most fictional character on ER, Luka Kovac gives us all kinds of unrealistic expectations and he is our number one pick in the ranking.