Oona O’Brien is a 19-year-old actress and former child model who gained recognition for playing Devon Lee in Netflix’s martial arts series Cobra Kai (Seasons 4-6). Born on September 15, 2006, she stands at 5’7″ (170 cm) and has become known for portraying a competitive, driven character who challenges stereotypes about Asian-American women in media.
Before her breakout television role, O’Brien worked with brands like Nike, American Girl, Sears, and Kmart, and participated in theater productions across multiple venues.
This biography covers her early modeling career, athletic training, breakthrough casting in Cobra Kai, character development as Devon Lee, relationships with co-stars, and her impact on Asian-American representation. As of September 2025, O’Brien balances her acting career with college applications while reflecting on the series finale.
Oona O’Brien Quick Bio/Wiki
Facts | Details |
Full Name | Oona O’Brien |
Date of Birth | September 15, 2006 |
Age | 19 (as of September 2025) |
Height | 5’7″ (170 cm) |
Profession | Actress, Former Model |
Notable Role | Devon Lee in Netflix’s Cobra Kai (Seasons 4-6) |
Ethnicity | Asian-American |
@obrien.oona (700,000+ followers) | |
Representation | Paonessa Talent Agency, Brave Artists Management |
Athletic Background | Competitive swimming, ice skating, snowboarding, soccer, karate |
Early Career and Background
Oona O’Brien started working as a child model before transitioning to acting and theater. Her commercial portfolio included campaigns for major retailers and children’s brands, giving her early exposure to professional sets. Industry records show she appeared in Nickelodeon and American Girl commercials during her childhood years.
Her theater background provided foundational acting skills through multiple stage productions. She performed in The Fig and the Wasp at Cara Haven Theatre, participated in Second City Youth Ensemble, played a lead role in Annie at Pepper Rising Stars Theatre, and portrayed Tomika in School of Rock at UAC Theatre. These experiences built her stage presence before cameras.
Before Cobra Kai, O’Brien’s only on-screen credit was the 2020 short film Sky High, where she played Mia Savage. She is represented by Paonessa Talent Agency and Brave Artists Management.
Oona O’Brien Physical Attributes

According to IMDb profile, Oona O’Brien stands at 5’7″ (170 cm), which falls above average height for American women. Her height contributes to her on-screen presence during martial arts sequences and allows her to match up physically with co-stars during fight choreography.
Her Asian-American ethnicity plays a central role in how she approaches the Devon Lee character. In a conversation with Netflix Tudum, O’Brien emphasized the importance of representation: “Devon is a fierce competitor and she really challenges that [stereotypical] notion of Asian girls being weak and submissive” (source: The Direct).
At age 19 (as of September 2025), O’Brien balances the physical demands of action-oriented roles with typical young adult concerns like college planning.
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Athletic Background and Skills
Oona O’Brien brought genuine athletic credentials to Cobra Kai beyond acting ability. She works as a competitive swimmer with years of training experience, providing the cardiovascular endurance needed for physically demanding shooting days. Her swimming background also developed body awareness and coordination that translated well to martial arts choreography.
Beyond swimming, O’Brien has experience with ice skating, snowboarding, and soccer. These diverse athletic pursuits made learning karate movements more intuitive. Co-star Xolo Maridueña praised her martial arts abilities in Seventeen Magazine: “Oona is really, really good,” noting that she impressed castmates despite having little karate experience before joining the show.
Peyton List mentioned O’Brien’s dedication to training in the Netflix Tudum article: “She’s going to karate camp where they sleep on the mats.” This commitment to authentic martial arts training rather than relying solely on stunt doubles demonstrated professional dedication beyond what many young actors provide.
Cobra Kai Casting and Introduction
Oona O’Brien joined Cobra Kai in Season 4, which premiered in late 2021. At just 14 years old when cast, she entered an established show with dedicated fans. She was already a viewer before auditioning, as she told Cobra Kai Kid: “It was like my favorite show too. We binged the whole thing as a family a couple weeks before I even got the audition. I was actually rewatching for a second time. I was over the moon” (The Direct).
Her character Devon Lee was introduced as a competitive student who joins Eagle Fang Karate under Sensei Johnny Lawrence (William Zabka). The casting required someone who could handle physical action scenes while bringing emotional depth to a driven, sometimes flawed character.
Her first day on set became a memorable initiation. As she shared with Netflix Tudum: “My first day on the set of Cobra Kai was my first day on any set, actually — and I spent that entire day kicking all the guys in the balls” (source: Netflix Tudum interview). This scene established both the physical comedy and Devon Lee’s no-nonsense fighting style.
Oona O’Brien: Devon Lee Character Analysis

Devon Lee evolved from an ambitious, ego-driven newcomer to a more mature team player who learns accountability across Cobra Kai Seasons 4-6. The character’s competitive nature mirrors O’Brien’s own personality, as she told Her Campus: “I definitely have her competitive mindset. I’m also very goal-oriented. I always have to have my Google Docs with all my goals. Devon’s sort of the same way. A little bit of type A” (source: Her Campus interview).
Season 6 brought significant moral challenges for Devon, including a controversial decision to spike competitor Kenny’s water before a match. O’Brien found this storyline difficult initially: “I didn’t believe it at first. I was like, no she would never, she would never. But she’s so competitive. I do get where she’s coming from. She wanted it so badly” (source: Pop Culture Unplugged).
The character’s redemption arc in Season 6 Part 2 allowed Devon to take accountability during an emotional scene with Johnny Lawrence. O’Brien noted this was her first time crying on camera and credited Zabka’s support: “Mr. Zabka was so great because he’s just such a comforting sweet person and he was like hey you got this you can do it.”
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Season 6 Storyline Details
Cobra Kai Season 6 divided into three parts throughout 2024-2025, with Devon Lee’s arc focusing on competition, mistakes, and redemption. Part 1 established Devon’s emotional vulnerability after losing her mother, creating a parallel with Tory Nichols‘ storyline. O’Brien described this connection: “They’ve both lost their moms and they have something to prove” (source: Pop Culture Unplugged interview).
The Sekai Taikai Tournament, an international competition filmed over multiple days, showcased some of O’Brien’s most challenging work. The massive brawl scene in Part 2 took approximately two days to film, requiring coordination among nearly the entire cast. O’Brien recalled one particular sequence: “We actually filmed that scene with me and Dallas [Dupree Young] sort of running up the stairs of the Sekai Taikai venue and fighting off the other teams… we filmed that in like 15 minutes. It was crazy fast” (source: Pop Culture Unplugged interview).
The international setting created fresh dramatic tension. O’Brien noted: “Miyagi-do students were finally like in a position where they aren’t the big fish and you know they have to they’re all sort of like Treading Water there” (source: Pop Culture Unplugged interview).
Oona O’Brien Key Relationships

Devon and Johnny Lawrence
The student-teacher relationship between Devon and Johnny Lawrence remained central to Devon’s character development. Johnny served as Devon’s primary sensei at Eagle Fang Karate, providing both martial arts instruction and life guidance.
O’Brien praised William Zabka’s supportive presence during difficult scenes. When filming her first crying scene, Zabka created a safe environment that allowed her to access genuine emotion. Despite Devon’s mistakes in Season 6, O’Brien confirmed Johnny’s continued faith: “He always had a thing for you that he always a top student throughout the season” (source: Pop Culture Unplugged interview).
Before being cast, O’Brien already identified with Eagle Fang Karate. She told Cobra Kai Kid: “I always knew I was Eagle Fang at heart.” She later confirmed to same Her Campus interview: “It’s a ridiculous name but you know that’s my first Dojo so have to stay true there” (source: Her Campus interview).
Devon and Tory Nichols
Devon Lee looks up to Tory Nichols as a mentor figure, particularly in Season 6 when both characters grieve their mothers. O’Brien explained: “Devon looks up to Tori a lot especially because they have sort of been going through the same story… losing their moms. I think she sees like a strong female role model in her and and she kind of just looks up to her and tries to follow her path.”
The parallel storylines allowed both characters to explore grief, anger, and redemption within competitive karate. Peyton List’s portrayal of Tory provided a template for Devon’s journey, showing how a fierce competitor can mature without losing her edge.
Devon and Kenny Payne
Devon’s relationship with Kenny Payne (Dallas Dupree Young) evolved from teammates to rivals (after the spiking incident) to reconciliation. The water-spiking storyline created real tension between the characters. O’Brien found reconciliation meaningful: “Dallas and I are good friends in real life so it was nice to be able to play friends on screen too.”
By Season 6 Part 3, Devon and Kenny reached better terms. O’Brien hinted at this resolution: “Now they’re just finally on good terms and you know a lot of the Miyagi do are feeling better about their feuds so a lot of that is resolved going into the third part of the series.”
Working with Industry Veterans
Oona O’Brien gained invaluable experience working alongside Cobra Kai veterans like Ralph Macchio and William Zabka. She described the cast as “just one big family” where everyone supports each other. The Netflix Tudum article highlighted how veteran actors have been generous in sharing knowledge with younger cast members.
Ralph Macchio directed Season 6, Episode 3, which featured the slumber party sequence. O’Brien recalled: “Mr. Macchio directed episode three which was the slumber party episode and you know he gave a lot of great advice there too and that was such an awesome experience. He’s a fantastic director.”
Xolo Maridueña acknowledged the younger cast’s rapid skill development: “Those three, Griffin, Dallas and Oona, oh my gosh. They’re younger than I was when I started on the show and they’re infinitely better.” Jacob Bertrand observed: “I’ve never really worked with actors that were younger than me. I was always the youngest one on the call sheet… Now you can teach or show people stuff.”
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Representation and Cultural Impact
Oona O’Brien has been vocal about the importance of Devon Lee as Asian-American representation in mainstream media. She emphasized this in multiple interviews, expressing hope that Devon could serve as a role model for young Asian-American girls.
The Karate Kid franchise’s historical connection to martial arts and Asian culture makes authentic Asian-American representation particularly meaningful. O’Brien hopes Devon’s legacy extends beyond the show: “I hope that Devon can be sort of a role model to a lot of those young girls out there especially like Asian-American girls because she is such a fierce and intense and strong personality that breaks a lot of the stereotypes of Asian girls being submissive and meek.”
Her portrayal challenged narrow media portrayals by showing that strong female characters of color can be competitive, make errors, and learn accountability without conforming to stereotypical “perfect” or “submissive” archetypes.
Oona O’Brien Personal Life and Interests

Beyond acting and athletics, Oona O’Brien has shared personal interests that reveal her personality. She’s a fan of Tyler, the Creator, particularly citing his album CHROMAKOPIA and the track “Balloon” featuring Doechii. She also mentioned enjoying the book On Earth, We’re Briefly Gorgeous, noting its meaningful quotes about coming-of-age experiences.
O’Brien maintains an active Instagram presence (@obrien.oona) where she shares behind-the-scenes content from Cobra Kai and connects with her growing fanbase of over 700,000 followers.
Career Impact and Future
As Cobra Kai concluded its six-season run in 2025, Oona O’Brien reflected on the experience: “There’s only so much fan service that you can give to help bring the audience in. Our creators and writers have done a great job of not only adding that nostalgia realistically and naturally but also being able to add on so much more.”
At the time of Season 6 Part 2’s release (late 2024), O’Brien was balancing her career with education: “I’ve been pretty heads in the book studying… just focused on school and studying right now.” She mentioned actively applying to colleges, demonstrating commitment to education alongside professional acting.
On the show’s conclusion, O’Brien expressed mixed emotions in the same Pop Culture Unplugged interview: “I do think it’s very satisfying and it’s also bittersweet because I’m going to miss these people so much.”
Legacy and Lasting Impact
Oona O’Brien’s portrayal of Devon Lee across three seasons of Cobra Kai left a mark on the franchise’s representation of young female fighters. Her character’s journey from ego-driven competitor to accountable team player mirrored real coming-of-age challenges.
Peyton List praised her maturity: “It’s amazing to watch them… there is a sense of wonderment that I have watching Dallas and Oona because they are so mature for their age.” This professional reputation at age 19 suggests strong career longevity.
Her commitment to authentic martial arts training set a standard for physical preparation. By attending karate camp between filming seasons and working with real martial artists, O’Brien ensured her fight scenes maintained credibility, honoring the Karate Kid franchise’s legacy.
Conclusion
Oona O’Brien transformed from a child model with theater experience into a recognizable television actress through her role as Devon Lee in Cobra Kai Seasons 4-6. Her athletic background as a competitive swimmer, combined with genuine martial arts training, allowed her to perform physically demanding action sequences with authenticity.
Working alongside industry veterans like William Zabka and Ralph Macchio provided mentorship that shaped her professional development. Her willingness to portray a flawed character who makes mistakes and learns accountability created more meaningful representation than stereotypical “perfect” role models.
As Cobra Kai concluded in 2025, O’Brien balanced her acting career with college applications. Her portrayal of Devon Lee joins the Karate Kid franchise’s legacy while representing modern stories about competition, redemption, and cultural identity.
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FAQ‘s About Oona O’Brien
How old is Oona O’Brien?
Oona O’Brien was born on September 15, 2006, making her 19 years old as of September 2025.
What is Oona O’Brien’s height?
She stands at 5’7″ (170 cm).
What character does Oona O’Brien play in Cobra Kai?
She plays Devon Lee, a competitive student who joins Eagle Fang Karate under Sensei Johnny Lawrence in Seasons 4-6.
Did Oona O’Brien have martial arts experience before Cobra Kai?
No, she had little karate experience before joining but brought athletic skills from competitive swimming, ice skating, snowboarding, and soccer.
What was Oona O’Brien’s first acting role?
Her first on-screen credit was the 2020 short film Sky High, where she played Mia Savage.
Is Oona O’Brien on social media?
Yes, she maintains an Instagram account (@obrien.oona) with over 700,000 followers.
What is Oona O’Brien’s ethnicity?
She is Asian-American and has spoken about the importance of Devon Lee as representation that challenges stereotypes.
Did Oona O’Brien do her own stunts in Cobra Kai?
She performed many of her own fight scenes after attending intensive karate training camps between filming seasons.
Is Oona O’Brien going to college?
As of late 2024, she was actively applying to colleges while balancing her acting career.
Who are Oona O’Brien’s talent representatives?
She is represented by Paonessa Talent Agency and Brave Artists Management.

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