Exclusive Interview: Sean Kaufman on ‘For All Mankind’ Season 5 and Alex’s Defining Journey

Few series operate on the scale of For All Mankind, yet what continues to set it apart isn’t just its reimagining of history—it’s how deeply human it remains. Built on the idea of an alternate timeline where the space race never slowed down, the series stretches across decades, tracking not only technological advancement but the people forced to keep up with it. It’s a world where progress comes at a cost, and every breakthrough leaves a lasting impact on the lives tethered to it.

By its fifth season, that vision has expanded in ways that feel both ambitious and intimate. What once began as a race to the Moon has grown into something far more layered, with shifting power dynamics, generational divides, and new frontiers that challenge what legacy really means. And yet, even as the scope widens, the series never loses sight of its emotional core—continuing to explore the tension between who we’re expected to be and who we choose to become.

At the center of that shift is Sean Kaufman, whose portrayal of Alex captures the uncertainty, pressure, and quiet resolve that define stepping into adulthood under extraordinary circumstances. There’s a lived-in quality to his performance that allows those internal struggles to surface in subtle, unexpected ways. As Alex begins to carve out his own identity within a world shaped by those before him, Sean grounds the journey in something deeply relatable. We caught up with him to talk about finding that balance, stepping into an established world, and the moments that define Alex’s path this season.

PC: You’ve experienced television from both sides—helping bring a series to life from the ground up with The Summer I Turned Pretty, and then stepping into an established world like For All Mankind. It’s always interesting how each project informs the next. How did those earlier experiences prepare you for this role? And how might this one shape what you carry forward into future projects?
Sean: I was actually just talking about this with Ron Howard the other day. He started out in TV as well—we were working on a film together—and he said, “I love working with TV actors.” I was like, “Really? Why—because we suck?” [laughs] I’m kidding.

But he said it’s because TV is such a machine. You’re moving through a certain number of pages a day, across multiple episodes, and there’s a rhythm to it. TV actors understand that they’re a cog in that machine, but the best ones still find their freedom within it. They know how it works, how to be efficient, and still bring something creative to the table.

I don’t love thinking of it as a machine, but there is truth to it. And it’s always really nice working with people who understand that balance—who know how to navigate the structure while still staying creatively open.

PC: Beautifully said. As part of your preparation for this role, you had the opportunity to speak with a NASA astronaut who walked you through the realities of that world. How did that conversation and research shape your approach to the character and help you fully immerse yourself in that environment?
Sean: He might hate me for this, but I spoke with Garrett Reisman, who was on the ISS. It was such a big moment for me—I wanted to be an astronaut when I was a kid. Who didn’t? So getting to talk to someone who actually lived that experience, I was completely enamored.

And honestly, he helped me chill out a lot. I was ready to walk in slow motion and be like, “What’s gravity?” [laughs] And he was like, “Dude, it’s just like Earth. It’s not that different.” He was like, “It’s a TV show—it’s really not all that different.”

That conversation grounded me. It reminded me that, yes, it’s set in space, but at its core, it’s about the human experience—relationships, family, character. It allowed me to relax and focus on that, instead of worrying about getting every technical detail perfect.

PC: There’s a groundedness to your performance, and it’s so cool to hear about wanting to be an astronaut because it feels like a full-circle moment for you. Your character’s journey is one audiences will really connect with—he’s navigating the cusp of adulthood and the expectations placed on him, both from others and himself. You deliver such a transformative performance, with so much of that internal conflict living in the quieter, unspoken moments. How did you find your way into this character and approach bringing that to life in such a visceral way on screen?
Sean: Thank you—that means a lot. When I got cast, they told me there was going to be a lot of “looking,” and I was like, “What does that even mean?” But as I started reading the episodes, I realized his world is really internal.

For most of the season, everything is happening beneath the surface. He’s carrying all of this pressure and these huge emotions that are constantly building inside of him. It’s really about that tension between inaction and action—he doesn’t want to make certain choices, but he feels like he has to.

Then there’s a turning point where, for lack of a better term, you see him become a man. That internal world finally shifts outward—he starts doing instead of just thinking. That was a big key for me, understanding when to let that internal life stay contained and when to let it break through into action.

PC: There’s so much to unpack in this performance. Without getting into spoilers, there were so many moments in Season 5 where it felt like, “Oh, this is a defining turning point,” and each person he encounters shapes who he ultimately becomes. Looking at that journey as a whole, who do you think has the biggest influence on the person we see him grow into by the end of the season?
Sean: That’s a great question. I think it has to be Ed. He’s had the biggest influence on him since he was born. Even going back to Season 4, Ed was pulling him into things he probably shouldn’t have been involved in at such a young age.

There’s this constant push and pull—wanting to live up to him, but also wanting to push back. The younger generation is always the one driving change, rebelling against the old guard, seeing them as set in their ways or out of touch. Alex definitely has that perspective at times—like, “Alright, grandpa, whatever.”

But I think that perception evolves over the course of the season. His relationship with Ed shifts, and ultimately, that dynamic probably shapes him more than anything else.

PC: It feels like, throughout the season, he’s carrying a sense of wanting to honor what his grandfather has built. On the flip side, for you, you’re stepping into a world alongside such incredible actors. Was there something you took away from working with any of your castmates this season?
Sean: A lot, honestly. Joel Kinnaman is an incredible human—he really helped me ease into this season. Just being able to talk with him and share scenes was such a gift.

Working with Ruby Cruz was also a dream. She’s become one of my best friends—just the sweetest person. Every scene we had together, we were trying not to laugh because she’s so funny.

But I think the biggest takeaway for me was actually what happened off camera. Some of my favorite moments were just all of us sitting in a green room, talking and getting to know each other. This cast is filled with such genuinely kind people. It would’ve been easy to feel nervous stepping into something like this, with all that pressure, but every single one of them made me feel completely at ease and at home.

PC: You deliver such an incredible performance here. You’re a real chameleon—each role feels completely distinct from the last—and every episode of this series plays with a cinematic scale, balancing emotional depth with high-stakes action. Is there a particular scene or episode you’re most excited for audiences to experience?
Sean: There definitely is—the last two episodes. I remember feeling a lot of pressure going into those. I really wanted to do them justice because there are some incredibly intense moments.

Those were the episodes where I kept thinking, “I really hope I got this right.” [laughs] And they’re also the ones I’m most excited for people to see. I’m really curious to hear how audiences respond to those moments.

To keep up with Sean, follow him on Instagram. Stream For All Mankind on Apple TV.

Photo Credit: Apple TV