Alex Garland’s 2014 directorial debut is basically a masterclass in claustrophobia. It’s tight. It’s sleek. It feels like a high-tech pressure cooker. But honestly, if you swapped out the actors in Ex Machina for a different trio, the whole thing probably would have crumbled under the weight of its own philosophical pondering. Most sci-fi movies get lost in the "how" of the technology, but this film stays obsessed with the "who."
It’s about three people (well, two people and a machine) trapped in a glass house in the middle of nowhere. That’s it. That is the whole movie.
When we talk about the actors in Ex Machina, we aren't just talking about a cast list; we're talking about a very specific moment in Hollywood history where three relatively under-the-radar performers were all about to explode into the mainstream. You’ve got Domhnall Gleeson, Oscar Isaac, and Alicia Vikander. At the time, they were respected, sure, but they weren't the household names they are now. Looking back, it’s kinda wild to see them all together in such a tiny, intimate setting.
Alicia Vikander and the challenge of being Ava
Playing an AI is a trap for most actors. Usually, they go one of two ways: they act like a stiff, monotone robot, or they act exactly like a human to show "growth." Alicia Vikander did neither.
She leaned into her background as a professional dancer with the Royal Swedish Ballet. It shows. Every movement is a little too precise, a little too deliberate. When she turns her head, it’s not just a neck movement; it’s a calculated shift of a mechanical axis. It’s unsettling.
Vikander has mentioned in various interviews that the physical costume—a mesh bodysuit that required hours of application—dictated how she breathed and moved. She couldn't just "be" a person. She had to be a construction. That duality is why the actors in Ex Machina worked so well; Vikander makes you want to trust Ava while simultaneously making your skin crawl. Is she a victim or a predator? The movie never quite tells you until the very end, and that's entirely due to how Vikander plays the ambiguity. She’s not just "acting" curious; she’s simulating curiosity to see if it works on her subject.
There’s a specific scene where she puts on a wig and a dress. It’s a pivotal moment because she starts to look "real." But Vikander plays it with this eerie blankness behind the eyes. It’s a mask on top of a mask. It’s brilliant.
Oscar Isaac as the tech-bro nightmare
If Vikander is the soul of the film, Oscar Isaac is the engine. He plays Nathan, the billionaire genius who lives in a brutalist bunker and spends his days drinking green juice, lifting weights, and getting blackout drunk. He’s basically the worst-case scenario of a Silicon Valley CEO.
Isaac is terrifying here.
He doesn't play Nathan as a cartoon villain. He plays him as your "buddy" who also happens to own your soul. He’s charismatic. He’s funny. He dances to disco music in one of the most famously bizarre scenes in modern cinema alongside Sonoya Mizuno. But there is a deep, bubbling violence just beneath the surface. Isaac’s performance is built on intimidation through proximity. He’s always standing a little too close to Caleb. He’s always touching him, patting him on the back, or looming over him.
The actors in Ex Machina had to deal with a script that was incredibly wordy, and Isaac carries the bulk of the "science" talk. But he makes it sound like a threat. When he explains the Turing test, he isn't lecturing; he's setting a trap. He’s the personification of the idea that just because we can build something doesn't mean we should.
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Domhnall Gleeson is the audience's proxy
Then there’s Domhnall Gleeson as Caleb. Poor, sweet, manipulated Caleb.
Gleeson has the hardest job out of all the actors in Ex Machina. He has to be the "normal" one. He’s the moral compass, but he’s also incredibly naive. Gleeson plays Caleb with this soft, stuttering vulnerability that makes him the perfect foil for Isaac’s hyper-masculine aggression.
You see him slowly unravel. By the time he’s cutting his own arm open to check if he’s a robot, you’ve completely followed his descent into madness. Gleeson’s performance is reactive. He’s the one we see the horror through. Without his genuine belief that he’s "saving" Ava, the ending wouldn't hurt nearly as much. He’s the "nice guy" who realizes too late that he was never the hero of the story; he was just another component in a test.
The overlooked presence of Sonoya Mizuno
We have to talk about Kyoko. Sonoya Mizuno doesn't have a single line of dialogue in the entire film. Not one. Yet, she is arguably the most haunting presence among the actors in Ex Machina.
Mizuno, also a dancer, uses her body to communicate a level of subservience that is deeply uncomfortable to watch. She’s Nathan’s assistant/servant/object. The way she moves around the kitchen, or the way she stands perfectly still while Nathan berates her, adds a layer of "house of horrors" to the mansion.
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The dance scene—often referred to as the "Disco Dance-Off"—is the moment where the movie shifts from a psychological thriller to something truly surreal. It’s choreographed perfectly, and the contrast between the upbeat music and the dead-eyed precision of Isaac and Mizuno is peak cinema. It tells you everything you need to know about Nathan's ego without saying a word.
Why the chemistry (or lack thereof) mattered
The magic of the actors in Ex Machina is that they feel like they belong in different movies, which is exactly why the tension works.
- Nathan (Isaac) is in a corporate thriller.
- Caleb (Gleeson) is in a romantic drama.
- Ava (Vikander) is in a prison break movie.
When these three perspectives clash, the audience is left off-balance. You don't know who to root for. Garland’s script provides the foundation, but the actors provide the texture. If Gleeson was too confident, we’d expect him to win. If Isaac was too obviously evil, we wouldn't believe Caleb stayed in the house. If Vikander was too robotic, we wouldn't care if she escaped.
The film was shot in Norway and at Pinewood Studios on a relatively small budget of about $15 million. Because they couldn't rely on massive CGI set-pieces, they had to rely on the faces of these three people. Even Ava’s robotic parts were added later via VFX, meaning Vikander had to give a performance that was compelling enough to survive the digital "removal" of her limbs and torso.
The lasting impact of the performances
Since 2014, these actors have gone on to dominate the industry. Oscar Isaac became Poe Dameron in Star Wars. Domhnall Gleeson became General Hux in the same franchise. Alicia Vikander won an Oscar for The Danish Girl and became Lara Croft.
But for many cinephiles, this remains their best work.
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It’s rare to see a film where every single performance is so perfectly calibrated. There are no "weak" links here. Even the minor roles, like Corey Johnson as the helicopter pilot at the beginning, serve to ground the world in a reality that feels just five minutes away from our own.
The legacy of the actors in Ex Machina isn't just that they made a cool movie; it’s that they made us ask questions about consciousness, consent, and what it means to be alive. They took a "bottled" script and turned it into a sprawling epic of the mind.
Actionable Insights for Fans and Aspiring Creators
If you’re revisiting the film or studying it for its performances, keep these points in mind to truly appreciate the craft:
- Watch the eyes, not the mouth: In the scenes between Caleb and Ava, notice how Vikander uses micro-expressions. She rarely blinks. This was a deliberate choice to highlight her non-human nature.
- Observe the use of space: Pay attention to how Oscar Isaac occupies the room. He is almost always "taking up" Caleb’s personal space, a classic power move used in high-stakes acting to create organic tension.
- The Power of Silence: Rewatch Sonoya Mizuno’s scenes. Notice how much she communicates about the history of Nathan’s experiments without uttering a single word. It’s a masterclass in non-verbal storytelling.
- Contrast the movement: Compare the way Nathan moves (loose, heavy, grounded) to the way Ava moves (light, precise, ethereal). The physical contrast tells the story of the creator vs. the creation better than the dialogue ever could.
To fully understand the impact of the film, look for the "behind the scenes" footage showing Vikander in her gray "tracking" suit. Seeing the raw performance before the VFX were added proves that the character's humanity—and lack thereof—came from the actor, not the computer.