Eoin Macken: Finding Truth and Tension in Borderline

I liked the fact that it still has that north–south dynamic — professional and personal — without being some big overplayed 1990s thing. It’s still a real issue that exists, and I enjoyed that. Then, by creating that world, John brought in these really interesting topics in the later episodes — things like immigration, how you deal with past histories, and other political themes.

I remember thinking, this is actually an exciting, potentially great show. There’s also a bit of dark humour that becomes more apparent as the story develops, and I liked that too. Overall, I just thought the potential of what Borderline could become was super fun.

The show’s tone feels gritty and emotional. How did you find that balance on set?

Eoin Macken: I think that really came from the writing. This is a very writer-driven show, and all that tone and rhythm were already on the page. What you’re doing as an actor is just making that live.

For me, the most important thing was the dynamic with Amy. As long as those two characters felt real and existed truthfully together, everything else would naturally fall into place. That was the key to balancing the grit and emotion.

With your co-star Amy De Bhrún, who plays Detective Regan — she’s a right pain in the a** on screen. Did she stay in character throughout the series, or could she just flick a switch?

Eoin Macken: Amy’s f***ing hilarious. She’s one of the oddest, funniest people I’ve ever met. She was really pushing against playing the character as this super straight, hard-nosed type — she wanted Regan to have a bit more humour and warmth, which develops as the show goes on.

She starts off as a right bell-end, but that gives her somewhere to go. Amy fought to bring levity into the role, and it really works. It’s a slow-burning show, so she becomes far warmer when you get into the later episodes. I think they deliberately wanted her to start off harsh and cold, but honestly, she’s mad as a box of frogs — in the best possible way.

Working with Amy De Bhrún as your counterpart, was there ever a moment when your approaches to a scene diverged — and how did you reconcile that?

Eoin Macken: Yeah, probably, especially at the start, when we were trying to figure out the dynamics. I think it was actually harder for Amy because her character is more aggressive throughout. That gave me a chance to be a bit more reactive to what she was doing — she’s a pain in the a** on purpose, and that allows my character to bounce off her energy.

She had a tougher strike balance, but we enjoyed working together. I think that’s why the two characters work so well — there was a good vibe between us. It would’ve been a nightmare if we hadn’t enjoyed each other’s company, because we’re in almost every scene together. But it was easy and fun.

It reminded me of working with Jill Flint on The Night Shift, when we had that same rapport — that sense that the characters had room to grow. That’s why I hope people respond to it and we get to do another season, because these characters have so much rope to develop now.

Borderline feels timely. Did real-world events influence how you approached your role?

Eoin Macken: Yeah. My little sister’s boyfriend is from the north, about an hour outside Belfast, so I spent some time there doing research. Everything that’s happened with Brexit has kind of reopened a lot of the old divisions up there.

Some of that’s been tempered, but it’s still bubbling under the surface. Things like nationalism, immigration, and economic strain all play into that tension — and I think those same themes are woven through Borderline. That’s what made it feel so relevant to me.

And did you get much creative freedom then that helped you shape your character during filming?

Eoin Macken: Yes and no. I’m a huge fan of John Forté — we stay in touch all the time, and hopefully we’ll get to do seasons two and three, which I’d love to direct on. I want to keep working with John because he’s collaborative and open about where the show can go next.

For season one, John already had everything mapped out — his vision was clear — but I was allowed to find the character’s reality within that. I could adjust how I wanted to make him feel authentic, and that freedom helped me ground him. Amy and I also had time to explore our dynamic and build something genuinely lived-in.

Was there a particular scene that pushed you hardest as an actor?

Eoin Macken: I think the most complex parts were the family scenes. They’re relatable but deceptively tricky — easy to act, but hard to make completely real, especially alongside the working relationship stuff with Amy. Those scenes came naturally; they were fun. But the family moments had to ring true emotionally.

I’m not a cop, and that was another challenge — making him believable as someone from that part of the world. There’s a big cultural difference between growing up Catholic or Protestant, even down to how people sing or pray in church. I went to services up there just to listen. There’s a different feeling and energy, which helped me understand the character.

Borderline looks cinematic — how important was the visual style in telling this story?

Eoin Macken: We had no sunshine. It just rained every day — never sunny. Our DP was like, “Let’s just go home.” But honestly, that look became part of the atmosphere.

That part of the island is dark and rich in history — all the old colours and Irish mythology live up there. It’s really beautiful. I think they wanted to capture that sense of scope, especially because the story isn’t set in Dublin or Belfast. It’s somewhere in between, with this unique latitude and mood.

It’s stunning up there, but we were there the whole summer, and I swear to God, it rained nonstop.