HBO Max's The Staircase explores the true story of the death of Kathleen Peterson and her husband Michael's subsequent trial and murder conviction. The series' star-studded cast features Colin Firth, Toni Collette, Patrick Schwarzenegger, and Sophie Turner, as well as Outer Banks' Cullen Moss, who portrays District Attorney Jim Hardin.

Hardin worked alongside Assistant DA Freda Black, played by Parker Posey, as part of the prosecution in Michael's trial in 2003. Created by Antonio Campos and Maggie Cohn, The Staircase received a pair of Emmy nominations, as Firth and Collette were tabbed in the categories for Outstanding Lead Actor and Actress in a Limited or Anthology Series or Movie.

Related: How Much HBO Max Changed Of The Staircase's True Story

Screen Rant spoke with Moss about his experience playing Jim Hardin in The Staircase.

 

Cullen Moss as DA Jim Hardin in The Staircase

Screen Rant: Congratulations on The Staircase. Have you had the chance to sit down and watch the whole thing yet?

Cullen Moss: I am embarrassed to say that I still have an episode to go on it. But I've watched almost all of it. I couldn't be happier with how it turned out. Antonio, and Maggie, and everybody involved, they just really made something cool.

How did you prepare for your role as the DA Jim Hardin? What kind of research was involved?

Cullen Moss: I just watched a lot of the old Perry Mason show. I'm kidding. I didn't. But I did growing up. I watched the documentary. I watched hours and hours of Court TV, especially all of Jim and Freda's, the testimony where they were questioning. I watched interviews with Jim Hardin, read up about him. I read up on the case and then Parker and I got to have almost a two-hour Zoom call with Jim where we got to talk about the culture in the DA's office, about him, about Freda. Also, there was a woman, Candy, who worked in the DA's office, who gave us a lot of insight.

But talking to Jim was crucial. It was invaluable to get to talk to Jim and actually get to know him a bit outside of what you see in the documentary, on Court TV, with interviews. There's a performative aspect to all of that that you can transcend when you get on a conversational level with somebody.

What was the most interesting thing you learned from talking to Jim?

Cullen Moss: Some of it was how early on he had decided that he wanted to be a lawyer, that that's how he wanted to serve his community. His father was from Canton, North Carolina and my step mother has relatives from that part of the state. We have land near there, so it was just that whole small world aspect of it all reared its head. I'm from Winston-Salem, North Carolina. That was interesting.

His father taught him early on that it was important to serve the people in your community and find a way to do that. After this horrible family tragedy, he was taken under the wing of a good family friend — or maybe it was an uncle — who took him somewhere, and this guy was a lawyer. He just got Jim out of Durham as a kid. He was a teenager and this guy would take him to work with him sometimes, and so he got to see how this guy served his community. That was really interesting and brought things home to me, and put things on a very human level. He came across as genuine and altruistic. It definitely softened some edges for me.

Of course, this series was a dramatized retelling of the real-life case and the people involved. Was your goal to imitate Jim to a tee or did you take any liberties with your portrayal?

Cullen Moss: I went pretty straightforward. I mean, there were some liberties, because for the scenes that came from Antonio's imagination or Maggie's imagination, they just had to imagine what happened. I couldn't presume to know exactly what Jim would do. So in that, those are artistic liberties where you fill in the blanks.

But I really wanted to hone in on him as much as I could. I think Parker did a lot of the same with Freda. Because those characters were so particular and recognizable for people familiar with the case, I wanted to get as close to him as possible. And there are a few things when the emotion goes outside of the range of anything I've ever seen Jim telegraph, that's where being an actor comes in and you just figure that out. How would Jim act in this? I wanted to be very true to him.

What was the most challenging part about playing a real person?

Cullen Moss: Just hoping that you're doing that person justice, that you're doing this real story justice, that you're honoring the gravity of everything at hand, and that you're honoring the people involved — and Jim in particular. I didn't want to do anything disingenuous that he could look back on and shake his head at [Laughs]. I wanted him to be OK with it, and I feel like the script was safe enough that I did that.

But it's surprising - even after I thought I portrayed him very truthfully and even-handedly, and I thought the writing was even-handed too - how many people, after having seen it, would say to me, "Ah, man, you played that bad lawyer." People interpreted me as this guy that was out to get Michael. I didn't see it that way. I certainly didn't play it that way, so it's interesting. You only have so much control over that and that's the hard part.

Did you learn anything new about the legal system in general or about this case?

Cullen Moss: Some things. Watching Court TV and living — you feel like you're living the trial — it was so surreal some days. In that court set, we had a beautiful production designer who just crushed it and made us feel totally immersed in the story. And, of course, all the actors you're surrounded by — brilliant people and fun people. Parker was amazing and is now a lifelong friend. I'm so grateful for that. But yes, regarding the justice system, I guess it's not a new thing but I just experienced it in a new way that there's not a perfect way to do this thing right now. We're still a work in progress and our judicial system certainly is.

The show had shown a light on all the variances of truth and the idea of truth itself. There's what happened and then there's everybody's interpretation of what happened. In a case like this with no witnesses, you can only hope to get there somehow and hope that the system works. I still don't know if it did or not in that situation. That was the whole documentary crew's examination of that case in particular. It was about the American justice system — does it work? So, it was illuminating in how nuanced all that is and there's no "this was wrong and this was right." It's hard to say and I hope that doesn't sound too flimsy, but that's kind of what I came away with.

The Staircase Synopsis

Colin Firth and Toni Collette looking upwards in HBO Max's The Staircase

The Max Original limited series, THE STAIRCASE, starring Colin Firth and Toni Collette, explores the life of Michael Peterson, his sprawling North Carolina family, and the suspicious death of his wife, Kathleen Peterson. Starring alongside Colin Firth and Toni Collette are Michael Stuhlbarg, Juliette Binoche, Dane DeHaan, Olivia DeJonge, Rosemarie DeWitt, Patrick Schwarzenegger, Sophie Turner, Vincent Vermignon, Odessa Young and Parker Posey. The Max Original is co-produced by Annapurna Television. The series is written and executive produced by showrunners Antonio Campos and Maggie Cohn.

Check out our previous interview with The Staircase EP Maggie Cohn as well.

Next: The Staircase Cast Guide: What Every Real Life Person Looks Like

The Staircase is available to stream on HBO Max.