The actor is now cancer free as his character, Jacob Monroe, goes through a similar health journey in season 3
Netflix
NEED TO KNOW
- Louis Herthum is opening up about his unexpected health journey and how it impacted his character’s story in season 3 of The Night Agent
- The actor, who is now cancer free after a diagnosis with prostate cancer in late 2024, tells PEOPLE that seeing his character of Jacob Monroe go through a similar journey was “euphoric”
- The Night Agent season 3 is now available to stream on Netflix
Louis Herthum has been a regular on television for over three decades. Fans may know him from his stint in Murder, She Wrote in the '80s and '90s or perhaps his best-known performance as Peter Abernathy in Westworld. But no role could ever hit as close to home as his character's latest arc on The Night Agent.
Playing villainous businessman Jacob Monroe since the show's second season, the actor was planning to return to set as usual in February 2025 to film season 3, with more dialogue this time around. Two months before filming, however, he got a diagnosis that changed his whole approach. It changed his character's fate, too.
After a prostate-specific antigen (PSA) test in December 2024 — following months of premature ventricular contractions, followed by MRIs and CT scans — Herthum's doctors diagnosed him with prostate cancer. At the time, his PSA was "extraordinarily high," he says.
"Here I am, a few months away from filming, knowing that I'd already lost about 15 or 20 pounds by then, knowing that I had to go through chemotherapy, knowing that I was going to lose my hair. I had a full beard in season two, I was going to lose that," Herthum, 68, tells PEOPLE of his thought process going into season 3.
Before filming, though, he got a call from series creator and showrunner Shawn Ryan. Herthum explained his diagnosis and Ryan had an idea. "I told him the situation. And the very first thing out of his mouth was, 'Lou, health is the most important thing to us, so whatever you want to do, that's fine. But if there's a way we can work this out, we'd love to.'"
He adds, "That was just unbelievable to hear, because I really thought they might have to replace me, write me out, kill me between seasons or something like that."
Ryan, 59, wasn't planning on removing Jacob from the storyline, Herthum says. Instead, he was willing to write in Herthum's real-life health journey. "He said, 'Well, buddy, listen, I don't know how you feel about your privacy around this, but how would you feel if we wrote it into the script?'"
Herthum's response: "I was hoping you'd say that, because that's the only way it's going to work.'"
Netflix
So Herthum got to work on The Night Agent alongside the rest of the cast and crew, including star Gabriel Basso (Peter Sutherland).
He was "lavished" with accommodations ("talk about an embarrassment of riches") and says the team "bent over backwards" and "completely just took me under their loving arms" to make sure he was comfortable filming following his diagnosis. At the time, he was flying back and forth from Baton Rouge to get treatment in New York. "It was tough because chemo is a b—-, man. I mean, it wrecks your body."
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Herthum tells PEOPLE he initially thought he was out of a job unless his character's story was altered, calling the decision by The Night Agent team "euphoric." While filming, those on set even tapped a body double for scenes where Jacob had to run, he says. "Another thing about this season, Jacob has a ton of dialogue, a ton of dialogue," Herthum says, "so I remember very vividly getting off of that call with Shawn when we decided we were going to make this work and going, 'Wow. What did I get myself into?' Because I wasn't feeling very good, and I knew this was going to be very difficult."
"But oddly enough," he continued, "that's one of the things that made it work so well and helped me recover, because I had so much dialogue to concentrate on."
"I had something to fill my time and not worry about my condition, just say, 'Buck it up, go,'" he adds. "This is not going to be easy, but you've done things that were not easy before."
JC Olivera/Variety via Getty
While viewers can find out what happens with Jacob's journey on The Night Agent, the man who plays him is now healthy and cancer-free. In September 2025, he says, his PSA was back in the "normal range," at 4.4.
"My doctor told me, from the very first meeting that I had with him, he said, 'Lou, I've seen a lot of men in the situation that you're in. Those with a really positive attitude are still around and still kicking,' " the actor recalls.
"And he said, 'Those that took the negative approach, they're not with us anymore.' So that's another thing, I just at that point said, 'OK, look, I'm beating this. This is not going to get me. Cancer's not going to take me,' he adds. "And so, it wasn't that big of a surprise, I expected it and I kind of manifested it."
The diagnosis also helped him connect more with his character, Herthum says, explaining that he's learned through the experience that "what does not kill us makes us stronger."
"I was 68 years old when this all happened. I'd been healthy my whole life, I hardly had ever got sick, I never had any real ailments or anything like this," Herthum reiterates.
"Your health, no matter how successful you are in life, no matter how much money you make in life, you've heard it a million times, without your health, you really have nothing," says the Home Before Dark actor. "And so, I encourage men of really any age, getting a simple blood test, get your prostate checked… Take care of yourself, because it's the most valuable thing that we have."
The Night Agent season 3, which Herthum says features "a lot of surprises" and "jaw-dropping moments," is now available to stream on Netflix.
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