Hamilton” star Daveed Diggs booked the role of Andre Layton in the small-screen adaptation of “Snowpiercer” less than a year after taking his final Broadway bow in Lin-Manuel Miranda’s musical. But it’s only now, exactly three years after his casting in the pilot was announced, that he’ll finally be seen in that role — a former homicide detective who now lives in the Tail of a 1,001 car train speeding around a frozen Earth. After a near-complete pilot reshoot, showrunner swaps and multiple network moves, “Snowpiercer” will launch on TNT on May 17.

Given the length of time this show was in the works, and the amount of changes it went through with different showrunners and reshooting the pilot, how different is the show you ended up making from what you thought you would be making, and what made you want to stick through it, even if the show it became was very different than for what you initially signed up?

What I was excited about what exploring the world — it seemed like a very, very expansive world, and that’s the big difference between the TV show and the film. In TV you have so much more space to explore this thing. But I didn’t know the mechanics of it. So one of the bits of misdirection in the show is that it’s a murder mystery: That is the inciting incident, but it ends up being a show that is a lot more about the politics of scarcity and how does this society function with limited resources; what are the complications of class in that setting? Certainly in those first few episodes I’m solving a murder, but what I end up getting embroiled in is a revolution, and the ramifications are so much bigger. Layton left the Tail to get information and potentially one day start a revolution, but he ends up where there’s no going back — whether he’s gathered enough information or not, he has to start. So, early on when I’m really focused on gathering intel, sneaking pens in and out of places and trying to figure out how to get messages back to the Tail, it’s an espionage type show where everyone is hiding something, but then one it erupts, we’re just fighting. It’s days and days and days of endless violence and being covered in blood on that set. The story spirals out of control in a way, and I think the experience of it was kind of that, too. It went from sneaking around to being right out in the center, yelling and throwing axes and getting the s— beat out of me.

Who was Layton, as he was first described to you, and how did that change as time went on?

I knew before the train he was a detective on the South Side of Chicago; I knew he worked homicide and he was really good at it; I knew that he was with somebody when he got on the train and [that person] left him and moved up. There were these ideas that felt like a lot to base the character on, but as the case with any television, new scripts would come with revelations about his past, but also new actions that I would have to justify, “What does that mean?” There’s an idea of a hardboiled detective that I think Layton both embodies and challenges, in a lot of ways. But as I spent more time without throughout the season, I just kept learning more and more about him, and that added specificity. He’s incredibly loyal to his people in the Tail, but he also starts to understand the necessity of compromise, and his loyalties get challenged in that respect. He’s super focused, but he has a lot that he’s also not dealing with with his past. So, his focus is on making the world better for the younger people on the train, but then he tends to overlook or not go back into his own past to deal with the trauma there. It’s really a story about trauma. That is the one commonality between everyone on this train: They have all been through a world-ending catastrophe. It’s really a story about, how can people deal with that within a society that’s trying to figure out how to operate around them?

How collaborative could you be on shaping who Layton became, given that you remained a constant with this production?

It would be a discussion about what is forthcoming for Layton and what that means for where he had been. There’s a pretty unique relationship between actor and writers’ room in TV where there’s this weird additive process where you get something and you interpret that, and then your interpretation inspires more things in the room, and then they get that back and it inspires new things for you. It’s like a game of telephone with two participants and neither of them hear each other really well — it’s kind of a bad line — but that interpretation is what makes it interesting.

You mentioned the expansive world. The distinction between classes and functions of the cars are so detailed, yet confining at the same time, given it is all set on a train. How did the setting affect how you wanted Layton to carry himself through the world?

The sets are beautiful and for sure a star of the show and they do a really great job of making you have to act less. You get into those spaces, and there’s incredible ingenuity for how things are built. If you look closely in the Tail, the beds there are all made out of stuff that was clearly raided from people’s luggage. You may never really see everything in a shot, but the attention to detail is wild. And it is also a pretty tight space, and it is filled with 300 people.

Which feels like another world right now in more ways than one.

That’s true. We were not social distancing while filming “Snowpiercer!” But that was one of the things that really affected my performance: You can’t tell a secret back there, so there are a lot of head signs that the Tailies use — things that the rest of the train doesn’t have to deal with because they’re not as close together. All of these things lend themselves to the character.

The commentary the show makes on class and climate changes is extremely topical right now, despite the futuristic setting. What did you want to say, politically, with the show?

I hope some people find some escape in it. It is fun, it is exciting, but it is definitely a cautionary tale. My job as an actor is not really to think about the messaging of the thing, but it is one of the things that made me interested in the show. The reason for sci-fi to exist is to examine ourselves. It creates a distant enough allegory so that we can look at ourselves in a way that challenges us.

Speaking of challenges, what were some of the more complicated aspects of Layton’s journey in Season 1 for you to perform?

I didn’t realize how difficult it would be to explore the amount of loss that Layton has and continues to experience. Everyone’s coming with a baseline of loss, but Layton risks everything and loses a whole lot over the course of the season. Any time we had to explore that loss, it was hard for me to get to sleep that night. The other was the really extremely violent scenes. I’ve never done a big action thing before, and I was very excited to do those, but it doesn’t cost you nothing to spend a whole day stabbing somebody. It took way more from me than I would have expected. I think that’s a good thing, but ultimately it was tough going home on those days and washing all of the fake blood off and having to live with the repercussions that don’t exist in the world of the show because there the war continues and you just move on. We had this amazing stunt team that made everything look and feel super real, so it didn’t feel like I was pretending to smash a bottle over a guy’s head; it felt like I was smashing a bottle over a guy’s head, and it felt like we did 100 takes of it!

How much did the stamina you built up from having to perform for hours on end on stage help with some of the physicality of these stunts?

I’m pretty good with the physical stuff, and I would chalk that up to my stage work. There’s no stunt performer on stage, so I’ve had to learn how to figure out the choreography, and that is certainly part of it. And yeah, there is a kind of stamina that you get from stage acting, but it ends up being very different because on stage it’s about letting go of the moment — the moment is gone once it’s gone because you’re telling the whole story every night. But in film and TV you’re constantly tweaking the thing until you get it right, so you can spend hours on one moment or come back to it again tomorrow.

Layton is a leader in “Snowpiercer,” and you’re playing some other famous leaders, both in the “Hamilton” movie and in Showtime’s limited series “The Good Lord Bird.”

I wouldn’t compared Frederick Douglass to Layton.

Just the leader aspect, but what do you look for in roles right now that have led you to these?

The through-line I’m looking for is characters who are more complicated than they appear. I like when there’s stuff we don’t know about them. And the other through-line I’m pretty intentional about is I don’t like to glorify stupidity in my choices. I think it’s a political act, actually. I won’t play stupid people. And that’s not to say that they can’t be goofy — I do play a lot of funny characters — but I don’t like my characters to make choices that aren’t justified. If their experience can’t back up a choice that they’re making, I can’t abide that.

Things you didn’t know about Daveed Diggs:

Age: 38
Hometown: Oakland, Calif.
Most used app: Apple Music
Surprised to be recognized for: Being a member of the rap group Clipping
Childhood hero: His dad
How he got into character for “Snowpiercer”: “I went deep into contemporary rap because that’s what I imagined Layton would have been listening to the last time there was downloadable music.”