'9-1-1' Officially Confirms Its Season 10 Buck Replacement

5 days ago 25

Oliver Stark as Buck in '9-1-1' flashes a big smile at something off camera

Published Oct 24, 2026, 2:38 PM EDT

Jennie Richardson is a TV Features and Lists Writer for Collider, and a graduate student pursuing an MFA in Fiction Writing. In other words, she really loves stories.

Now, 10 seasons in, one of the most rewarding parts of 9-1-1 has been Buck's (Oliver Stark) character arc. Buck started out in the pilot episode as a probie with unearned confidence who had a disregard for the rules and a lack of impulse control. Through his personal relationships with the rest of the 118 and his experiences on the job, though, Buck grew into a self-assured firefighter who approaches his job with care.

9-1-1 is officially two episodes into Season 10, and already, the show has given another character the opportunity this season to step into the space that Buck occupied as a probie in Season 1. This season, 9-1-1 has been making clear parallels between Harry Grant (Elijah M. Cooper) now and Buck when he was a probie. In Episode 2, "Fire in the Hole," Harry experiences his first loss on the job, marking a turning point for his character that will likely follow him the way that Buck's first loss back in Season 1 did for him.

'9-1-1' Season 10 Is Taking Harry on a Similar Arc as Season 1 Buck

Harry grew up in a family of first responders, and his experience of joining the 118 was already directly influenced by the loss of Bobby (Peter Krause), so he came into the job with a healthy respect for it. That said, much of Harry's experience at the 118 in Season 9 was about trying to convince Chimney (Kenneth Choi) to give him more to do. He was initially disappointed that he couldn't just jump into the action, but he has since been determined to work his way up. In the Season 10 premiere, Harry pulled a classic Buck move by doing something very reckless on the job. Harry's weight was keeping the 118 from being able to pull a victim out of the sinkhole, so he jumped off, putting himself in direct danger.

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Five hospitals. Five completely different ways medicine goes sideways on television — brutal, chaotic, romantic, brilliant, and ridiculous. Only one of them is the ward your instincts were built for. Eight questions will figure out exactly where you belong.

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A critical patient comes through the door. What's your first instinct? Medicine under pressure reveals who you actually are.

AStay completely present — block everything else out and work through it step by step, right now. BTriage fast and delegate — get the right people on the right problems immediately. CTrust my gut and move — I work best when I stop overthinking and just act. DAsk the question everyone else is ignoring — what's the thing that doesn't fit? ETake a breath, make a joke to cut the tension, and then get to work — panic helps no one.

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Why did you go into medicine in the first place? The honest answer says more about you than the one you'd give in an interview.

ABecause I wanted to be where it matters most — right at the edge, when someone's life is actually on the line. BBecause I wanted to help people — genuinely, one patient at a time, in a system that makes it hard. CBecause I was drawn to the intensity of it — the stakes, the drama, the feeling of being fully alive. DBecause medicine is the most interesting puzzle there is — and I needed a problem worth solving. EBecause I wanted to make a difference — and also, honestly, I didn't know what else to do with my life.

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What do you actually want from the people you work with? Who you want beside you under pressure is who you are.

ACompetence and calm — I need people who don't fall apart when things get bad. BTrust and reliability — I want to know that when I pass something off, it's handled. CConnection — I want colleagues who become family, even if that gets complicated. DIntelligence and the willingness to be challenged — I have no interest in people who just agree with me. EFriendship — people I actually like spending twelve hours a day with, because those hours are going to happen either way.

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You lose a patient you fought hard to save. How do you carry it? Every doctor who's worked a long shift has had to answer this question.

AI carry it. All of it. I don't look for ways to put it down — that weight is part of doing this work honestly. BI process it and move — you have to, or the next patient suffers for the one you just lost. CI feel it deeply and lean on the people around me — I don't think you're supposed to handle that alone. DI go back over every decision — not to punish myself, but because I need to understand what I missed. EI grieve it genuinely, find some way to laugh about something unrelated, and try to be kind to myself — imperfectly.

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How would your colleagues describe the way you work? Your reputation on the floor is usually more accurate than your self-image.

AIntense and completely present — no small talk during a shift, but exactly who you want there. BSteady and dependable — not the flashiest in the room but never the one who drops something. CPassionate and occasionally chaotic — brilliant on the hard cases, prone to drama everywhere else. DBrilliant and difficult — right more often than anyone else, and everyone knows it, including me. EWarm and self-deprecating — not the most intimidating presence, but genuinely good at this and easy to like.

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How do you feel about hospital protocol and procedure? Every institution has rules. What you do with them is a choice.

AProtocol is the floor, not the ceiling — I follow it until the patient needs something it can't provide. BI respect it — the system is broken in places, but the structure is there for a reason and I work within it. CI follow it until my instincts tell me not to — and my instincts are usually right, even when they cause problems. DRules are for people who haven't thought hard enough about when to break them. EI try to follow it and mostly do — with a few memorable exceptions that still come up in meetings.

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What does this job cost you personally? Nobody works in medicine without paying a price. What's yours?

AEverything outside these walls — I've given this job my full attention and the rest of my life has gone around it. BMy idealism, mostly — I came in believing the system could be fixed and I've made a complicated peace with that. CStability — my personal life has been as chaotic as the OR, and that's not entirely a coincidence. DMy relationships — I am not easy to know, and the people who've tried to would probably agree. EMy sense of gravity — I use humour as a coping mechanism, which not everyone appreciates in a hospital.

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At the end of a long shift, what keeps you coming back? The answer to this question is the most honest thing about you.

AThe fact that it's real — that nothing else I could be doing would matter this much, right now, today. BThe patients — individual human beings who needed something and got it because I was there. CThe people I work with — I have walked through impossible things with these people and I'd do it again. DThe next unsolved case — there's always another puzzle, and I'm not done yet. EBecause despite everything — the exhaustion, the loss, the absurdity — I actually love this job.

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Your Assignment Has Been Made You Belong In…

Your answers have pointed to one fictional hospital above all others. This is the ward your instincts, your temperament, and your particular brand of dysfunction were built for.

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You are built for the most unsparing version of emergency medicine television has ever shown — one that puts you inside a single fifteen-hour shift and doesn't let you look away.

You need your work to be real, not romanticised — meaning over drama, honesty over aesthetics.
You find purpose inside the work itself, not in the chaos surrounding it.
You've made peace with the fact that this job takes from you constantly, and gives back in ways that are harder to name.
Pittsburgh Trauma Medical Center demands exactly that kind of person — and you would not want to be anywhere else.

You are the person who keeps the whole floor running — not the most brilliant in the room, but possibly the most essential.

You show up, do the work, absorb the losses, and come back the next day without needing the job to be anything other than what it is.
You care about patients as individual human beings, not as cases to solve or dramas to live through.
You believe in the system even when it fails you — and you understand that emergency medicine is about holding the line just long enough.
ER is television about endurance. You have it.

Grey's Anatomy

You came to medicine with your whole self — your ambition, your emotions, your relationships, your history — and you have never quite managed to leave any of it at the door.

You feel things fully and form deep attachments to the people you work with.
Your personal and professional lives are permanently, chaotically entangled — and that entanglement drives both your greatest disasters and your most remarkable saves.
You understand that extraordinary medicine often happens at the intersection of clinical skill and profound human connection.
It's messy at Grey Sloan. You would not have it any other way.

House

You are drawn to the problem above everything else — the symptom that doesn't fit, the diagnosis hiding underneath the obvious one.

You're not primarily motivated by the patient as a person — though you are capable of caring, even if you'd deny it.
You work best when the stakes are highest and the standard answer is wrong.
Princeton-Plainsboro exists to house one extraordinary, impossible mind — and everyone around that mind is there because they're smart enough to keep up.
The only way forward here is to think harder than everyone else in the room. That is exactly what you do.

Scrubs

You understand that medicine is tragic and absurd in almost equal measure — and that the only sane response is to hold both of those things at the same time.

You are warm, self-aware, and funnier than most people in your field.
You use humour to get through terrible moments — and at Sacred Heart, that's not a flaw, it's a survival strategy.
You lean on the people around you and let them lean back. The laughter and the grief are genuinely inseparable here.
Scrubs is a show about learning to become someone worthy of the job. You are still very much in the middle of that process — which is exactly right.

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Everyone at the 118 has pulled a move like this at some point, but this was particularly risky, even though it ultimately worked. Still, 9-1-1 seems to be setting up an arc for Harry this season where he will determine the kind of firefighter that he wants to be. It's a different arc than the ones that Eddie (Ryan Guzman) and Ravi (Anirudh Pisharody) went through as probies, but it perfectly mirrors Buck's Season 1 arc. As Harry is slowly given more to do on the job, this naturally comes with finding balance when dealing with the dangers of the job, which comes into play when Harry loses his first person this week.

'9-1-1' Season 10, Episode 2 Is a Turning Point for Harry Like Season 2, Episode 2 Was for Buck

In Part 2 of Season 10's opening volcano emergency, Hen (Aisha Hinds) and Harry rush to the home of a woman whose smartwatch alerted 9-1-1 that she was hurt. The woman, Leona, was in her home when a large volcanic bomb went through the ceiling and landed on her abdomen. Leona has been a doctor for 16 years, and she quickly realizes that she isn't going to live. Leona tells Hen to leave her behind and join the rest of the 118 at the site of the eruption. Harry is unwilling to accept that Leona is dying, but ultimately, he tells Hen to go while he stays back alone. After Hen leaves, Harry just sits with Leona and keeps her comfortable, while she reflects on the first time she lost a patient.

It's a heartbreaking scene, as Leona tries to comfort Harry while she's dying, because she knows what it's like to be unable to save someone on the job. When Leona finally stops holding back her emotions, Harry cries with her before she dies. Every first responder on 9-1-1 has this defining moment in their career, where, for the first time on the job, they couldn't save someone, but this is particularly reminiscent of Buck's first loss on the job in Season 1, Episode 2, "Let Go." On that call, the 118 responded to an emergency on a roller coaster where one cart wasn't secured. One of the passengers (Caleb Castille) died, while the deceased's friend, Devon (Sean Liang), was left holding on in midair. Buck tried to save Devon, but Devon let go and died, and this loss was a defining moment for Buck. Now, Leona's death will follow Harry for the rest of his job, and this will be the turning point that defines his career.

9-1-1 airs Thursdays at 8:00 P.M. EST on ABC.