Tahar Rahim owes his UTA agent, Ali Benmohamed, a huge thank you. If it weren’t for Benmohamed’s insistence that Rahim read the script for The Looming Tower, in spite of Rahim’s blanket refusal to read anything that would cast Muslims as terrorists, he might never have played perhaps the most defining role of his career since his international breakthrough in Jacques Audiard’s A Prophet in 2009.

But so far, so agent. What makes Benmohamed so essential to Rahim chasing the role is his first name. When Rahim read the first two scripts for the Hulu miniseries, created by Dan Futterman, Alex Gibney and Lawrence Wright (and based on Wright’s non-fiction book of the same name) he liked what he saw in the character of Ali Soufan—a real-life FBI operative (and a Muslim) who Wright believes came closer than anyone to stopping 9/11. “These types of heroes existed 17 years ago,” he thought. “We should have portrayed them all those years ago. But better today than never.”

But Rahim was hesitant still. “I wanted to be polite, but I wanted to take some time,” he remembers. He spoke to the show’s creative team and told them he would call Ali. He meant Ali Benmohamed. “They thought I was talking about Ali Soufan, so they set up a Skype call with him by chance.”

Too polite to stop them, he took the call and was blown away by the person he spoke to. “He started to tell me about his life, and where this story would go,” Rahim says. “He said, ‘I’m one of the producers on this, so don’t worry; what I’m telling you is true.’”

Born in Lebanon, Soufan eventually resettled in the United States, graduating with a political science degree from Mansfield University of Pennsylvania in 1995. He joined the FBI soon afterward, and at 29 he caught the eye of John O’Neill, then head of the FBI’s National Security Division, who set him to work combatting a threat from Islamic fundamentalism that few believed could ever impact American soil. He met resistance from the big machine of American government, but it was Soufan’s intelligence, mined from a days-long interrogation of Osama bin Laden’s one-time bodyguard Abu Jandal, which gave investigators the clearest picture of al-Qaeda’s organizational structure and confirmed the identities of the 9/11 hijackers.

The Jandal interrogation is a key scene in the tenth and final episode of the show; it closes out The Looming Tower. As the two men spar in Lebanese Arabic, Soufan makes a piercing case for the contradiction between terrorist fundamentalism and true Islamic faith. It was the point of the show. “In 10 minutes, you can teach a lesson to the audience that a lot of TV news shows and debates can’t teach,” Rahim explains. “But in 10 minutes, in a dramatized scene, it becomes easy to understand. I was blown away by it, and at the same time, it’s just two people talking to one another. Playing chess with one another.”

For Rahim, all roads led to the challenge of getting that scene right. “It was 12 pages in Arabic,” he laughs. “I don’t speak it. I was so afraid of that scene, because if I screwed it up? It’s the end of the show; if it’s not working, you’re dead.”

He trained and prepared. He spoke at length with the Arabic cultural consultant on set, and he had been studying privately with a Lebanese-speaking coach. “I worked a lot,” Rahim admits. It was in the schedule for a day of shooting. “I remember they wanted to give me more time, too. They said, ‘We have one full day, and if you need more we can give you the day after.’ I was so prepared—and so scared—that we did it in less than a day. Three cameras, five takes, done.”

Rahim was already multilingual—we speak in English, though he was born in France to Algerian parents—but he had little hope of wrapping his head around conversational Lebanese. “I wish I could, but you never have the time to work on the basics,” he sighs. “You go on phonetics, and the more you learn it, the more you understand the music of the words. You start to get notions about what it all means, but not a lot.”

The scene is testament to the journey the idealistic rookie of the first episode has been on by the time of the finale. Rahim proffers that a key aspect of the show is the realization that Soufan’s private and professional personalities differed. It was there in the writing, but Rahim found it in the real Soufan, with whom he wound up spending a lot of time.

He usually saw the personal Soufan; funny, warm and still in love with the ideals of the American dream that propelled him to join the FBI. It was this spark of patriotism for his adoptive land that so confounded Abu Jandal. But at a book signing one day, Rahim saw Soufan’s other side. “He was scanning,” Rahim recalls. “He saw someone there and he said he started to suspect he had been from some kind of Secret Service abroad. I saw his look change. He had different eyes.”

Much of The Looming Tower revolves around the human frailties that caused so many of the slip-ups in the days leading to 9/11. Jeff Daniels’ John O’Neill is a man juggling multiple partners, up to his eyeballs in debt, and very easily discredited for it, even as he had the wisdom and intelligence to know what was going on before so many of his colleagues. Arguments between the FBI and the CIA amount to office politics on a devastating scale. O’Neill himself was forced out of the FBI before the 9/11 attacks. He took a job as the chief of security at the World Trade Center and perished when the second tower fell.

As for Soufan, he was a 29-year-old dealing with the tremendous mounting pressure of extremism at the very front line. “But when he talks about his experiences, it’s never heavy,” marvels Rahim. “He tells you funny stories. He tells you extraordinary stories, but it’s never heavy.”

Rahim takes a beat. “But it had to be heavy for him. He’s human. You must be so clever to be 29 and to deal with international problems every day. You have to be extremely clever and bold. There’s no other way.”

Rahim was 27 when A Prophet changed everything for him. It earned him trophies from the European Film Awards and the Césars. But it’s taken him nearly a decade to make his Hollywood debut. 70% of the roles he’s been offered since Hollywood saw A Prophet, he estimates, have been terrorist characters. “I had to say no sometimes to great directors because of the terrorist thing,” he remembers. Instead, he has focused on work from auteurs like Asghar Farhadi, Fatih Akin and Kiyoshi Kurosawa.

After a while, he says, he gave up waiting for the right call from Hollywood. “Only then did I have two offers—this and Mary Magdalene—come in at once. What’s the takeaway from that? When you stop dreaming about something it comes to you? I don’t know what to think about that.”

He wonders whether things are finally changing for minorities in Hollywood. But he never backed down from his commitment, even as his family expanded and the idea of an American paycheck might have appealed. “You have to feed your family, but what are you going to teach them?” he says. “When I was a student I remember I only had €300 [$350] a month to live on. You don’t need mountains of money. Life is good.”