Angelina Jolie’s penetrating eyes are filling with tears. “I don’t want to cry, and I’m not going to cry in front of you,” she vows, quickly regaining her composure.

The actress-filmmaker is choked up over the recent death of Louis Zamperini — a man who meant a great deal to her, and is the subject of her most significant directorial effort yet, “Unbroken.”

Zamperini, a former Olympic runner, was on a World War II search-and-rescue mission when his plane went down in the Pacific. He was lost at sea for 47 days before being sent to a Japanese prison camp. Over his two years there, he was starved, beaten and faced an adversary known as the Bird — a Japanese officer named ­Mutsuhiro Watanabe, who singled him out for torture. Zamperini returned home a haunted man, but overcame alcoholism to become an inspirational speaker. His life was chronicled in Laura Hillenbrand’s 2010 best-seller “Unbroken,” which Jolie adapted to the bigscreen for a Christmas Day debut.

On this August afternoon, it has been only five weeks since Zamperini died at the age of 97 due to complications from pneumonia. Jolie is seated in a room at a Beverly Hills hotel, flanked by two of the stars of her film, Jack O’Connell and singer-songwriter Miyavi, who play Zamperini and Watanabe, respectively. Along with the pressure of being involved in one of the most anticipated films of the year, everyone clearly feels a huge responsibility to Zamperini’s legacy.

“They say you should never meet your heroes, because they often disappoint you,” Jolie notes. “But Louis really was one of the greatest people ever.”

Art Streiber for Variety

As compelling as Zamperini’s story ­is, it was not an easy sell. Possibly the long­est gestating project in Hollywood history, it took 57 years to turn his tale into a cinematic reality. Actors from Tony Curtis to Nicolas Cage at one time or another were attached to the role, and many directors came and went. In the end, it was an Oscar-winning actress with only one little-seen feature film to her directing resume who shepherded the $65 million film to the silver screen. It is by far Jolie’s most ambitious and riskiest directorial outing — her first big studio movie. And she did it without any marquee names in her cast; in fact, one of the most pivotal roles was filled by a Japanese rock star who had never acted before.

In 1956, Universal Pictures acquired the rights to Zamperini’s just-published biography “Devil at My Heels,” but a script was never written and the project languished. In 1998, a CBS documentary about Zamperini’s life caught the eye of Matt Baer, who was then running the film division at Brillstein-Grey. Baer met with Zamperini and formed a fast friendship.

Over the next few years, Baer worked to get a film made. Scripts were written — an early title was “Iron Man,” one of Zamperini’s nicknames — and at one point Antoine Fuqua was attached to direct. But the project never came together. In 2002, Zamperini told Baer he’d received a letter from Hillenbrand asking to write his life story. Says Baer, “Lou said he was going to tell Laura, ‘Look, lady, I’ve already written my book, but if you want to write yours, go ahead!’ ”

But Baer was excited, knowing the book could help move the film along. What he didn’t know was that it would take the meticulous Hillenbrand eight years to finish the volume. During that time, Baer was still knocking on doors. “I would take our script and the CBS video around to every financier, saying there was about to be a big book about his life,” recalls Baer. “And everybody said no.”

When “Unbroken” was published in 2010, it was an instant sensation, spending more than 180 weeks on the New York Times Best Seller list. A new script was written by Richard Lagravanese (“The Fisher King”); when he left to make “Beautiful Creatures,” William Nicholson (“Gladiator”) came onboard. Still, Baer says, “The vast majority of directors passed.” Then the book found its way to Jolie after she read the logline at her agency, and she fell hard for the story of triumph. “There’s so much going on in the world today that could make you lose hope,” she says. “To read about somebody who had something inspirational and positive — it was fulfilling. I wanted to be close to his story. I wanted to go on this journey and become a better person.”

The story seems a perfect match for Jolie, an actor, director, mother, newlywed and humanitarian. A special envoy of the United Nations high commissioner for refugees, she has witnessed the effects of war in her worldwide travels. Fourteen years ago, when she first began working with the United Nations, she was shocked to learn the statistics concerning refugees. Since then, she says, she has always wanted to learn more and help more.

Art Streiber for Variety

Her passion was apparent in her first narrative feature, the 2011 drama “In the Land of Blood and Honey,” about the conflict in Sarajevo. Though it earned less than $2 million at the box office, among its fans was Universal Pictures chairman Donna Langley. “I’ve seen almost every film about that conflict, and I thought her film was the most impactful and clearest about what people were living through during that time,” Langley says. “The movie follows the story of a woman caught in difficult circumstances, who has to persevere; that’s very synonymous with Louis Zamperini’s story.”

But Langley didn’t just hand Jolie the job. “She had to work for it,” Langley notes. “I put her through her paces.” Baer says Jolie brought in boards using photographs that were representative of her vision for scenes and characters, and discussed what she wanted to do with the draft. “It was clear, well thought out, and filled with energy and passion,” he recalls.” Concurs Langley, “After a few conversations, it became very clear that she was ready to step up to the task.”

Once hired, Jolie met Zamperini, and a deep friendship ensued. As it turned out, the two were practically neighbors — Zamperini could see Jolie’s house from his office, and as Jolie was developing the film, she would climb on her roof and wave to him. Baer says it was a strong connection born of having many things in common. “They were both people who overcame obstacles as children. Both are highly physical. And both dealt with a lot of acclaim at a young age,” Baer notes. “Equally, they both ended up using their popularity to try to help others.”

Zamperini’s two children, Luke Zamperini and Cynthia Garris, say their father was smitten by Jolie.

“It was a very close and very affectionate relationship built on so much admiration and respect,” Luke says. He adds that Jolie’s husband, Brad Pitt, was also a fan. “When Brad was shooting ‘Fury,’ he was so excited to tell Louis he could drive a tank,” Luke laughs.

Adds Garris, “The night our father passed away, she and Brad came to our home and took such beautiful care of us. They cried with us, they held us, they made a soft place for us to fall. At one point I told her, ‘My father was really in love with you.’ And she said, ‘I was in love with him!’”

For as long as they could remember, Luke and Cynthia had watched their father try to get his story onscreen; it wasn’t until Jolie was onboard that they truly believed it would happen. “With her star power and her unbelievable focus, she got this film on the fast track,” Luke says. Adds Cynthia, “She really swooped in like an angel.”

Jolie enlisted a number of top talents who were big fans of the book, including Joel and Ethan Coen, who were tapped to write a draft of the script. “I couldn’t believe my good fortune,” Jolie says. “And being writers and directors, they write very visually, so I learned a lot from them.” The Coens’ frequent cinematographer, Roger Deakins, also signed on, as did composer Alexandre Desplat. “You can’t meet Angie and not say, ‘I want to work with her,’ ” Baer says.

In September 2013, the film officially got the greenlight to begin shooting the following month in Australia. To celebrate, Jolie posted an American flag on her roof for Zamperini to see.

Jolie knew the film wouldn’t work if she didn’t find a credible Zamperini and Watanabe. “These roles are so difficult,” she says. “And as an actor, I knew this film was going to rise or fall on these performances. They could sink the film if they weren’t brilliant.”

Art Streiber for Variety

Though name actors were discussed for Zamperini, the book was so beloved that it afforded Jolie the opportunity to cast whomever she wanted. But it was a tall order. “He had to be the appropriate age, because he was a young man at the time,” she notes. “It had to be somebody who had the strength and masculinity of that era — a real man’s man, a physical man. And at the same time, it had to be a skilled actor who can be deeply emotional and make people root for him.”

O’Connell, 24, is a British thesp best known in the U.S. for his work on the popular series “Skins” and in the thriller “Eden Lake.” When asked to submit an audition tape, O’Connell enlisted the help of his former drama teacher, Ian Smith. “We have a creative, rocky relationship, and he grilled me,” says the actor. “He told me what was sh-t about it, what was good. And by the time it was ready to send, I felt polished.”

According to Garris, O’Connell’s audition stood out for many reasons, but one that turned the tide. “It’s a scene in which he’s in confinement and being attacked by a guard,” Garris notes. “Jack was the only actor who fought back. I think that was a deciding factor for Angelina.”

Jolie went to London to meet O’Connell in person. That night, Baer says, “She emailed me, simply saying, ‘I found Lou.’ ”

He still had to screen test for Universal, and in a gesture for which he says he’s profoundly grateful, Jolie brought in O’Connell’s cousin to read with him. “He had done my taped audition with me, and I mentioned this to Angie,” O’Connell says.

Even after O’Connell got the part, he wanted the blessing of Zamperini. Their initial meeting was in a group, surrounded by cameras, but the second time they were alone. “We sat in his dining room, and he showed me his memorabilia and I got really emotional,” O’Connell admits. “He and his family welcomed me in, so I could go to Australia feeling I was championed by his people.”

Baer recalls that the first time O’Connell and Zamperini met, the latter showed off his original bomber jacket from the war. “Jack said, ‘Hey, can I try that on?’ And it fit perfectly,” Baer says. Garris adds, “Whenever I see Jack now, I call him Dad. He’s about as close as you can get to Louis onscreen, and we all adore him. We made him an honorary Zamperini for the rest of his life.”

While finding her Louis was difficult, casting the Bird seemed, in Jolie’s words, “impossible.” Watanabe was described in the book as “a beautifully crafted monster,” and Jolie was determined to find someone who was “striking, educated and intense,” and not a Hollywood stereotype of a Japanese person. Early on, she thought of casting a rock star. “There’s a confidence that comes from someone who’s a frontman,” she maintains. “It’s a very unusual thing to be able to be in front of thousands of people and have your presence affect a room.”

Jolie enlisted Japanese casting director and acting coach Yoko Narahashi in her search. Narahashi reached out to Miyavi (born Takamasa Ishihara), a guitarist and singer — but didn’t tell him what their meeting was about. “She came to my office in Tokyo and kept asking me questions like, ‘What kind of movies do you like? Who are your favorite actors and actresses?’ ” Miyavi recalls. “I said, ‘I really like Angelina Jolie.’ She just smiled.”

Jolie wanted Narahashi to meet with Miyavi before auditioning him, to find out what kind of person he was. “It’s important the soul of this person be a great man to play someone this complicated. He has to be somebody who’s in a healthy place in his life to be able to go to these places,” Jolie says.

Though he had never considered an acting career, Miyavi was thrilled at the prospect. Still, he hesitated playing such a sadistic character, worried it would reflect badly on the Japanese people. “But after meeting Angie in Tokyo, I was confident to be a part of this story,” he says. “We can all learn many things from this film, from the theme of forgiveness.”

By all accounts, it was a tough role for the 33-year-old father of two. “Once or twice when Angie called cut, he had to run off and vomit,” Garris says. “It made him violently ill to have to inflict so much anger and damage.”

Art Streiber for Variety

O’Connell also was struggling; to play the life raft and prison camp scenes, he estimates he lost around 30 pounds. He then had to quickly bulk back up for scenes of Zamperini as an Olympic runner. “We wrapped the prison camp scenes, and five days later, I was shooting a running sequence,” O’Connell notes. “Thinking about the example of endurance Louis set was invaluable. Because I was never going to suffer as much as Louis did.”

Though they play adversaries onscreen, O’Connell and Miyavi developed a friendly rapport when the cameras were off. “I actually thought I would keep my distance at first and try to stay separate,” O’Connell admits. “But the more we’d engage, the deeper our respect developed. In the end, his support of me and my support of him was important.”

While Miyavi says he wants to continue acting, his director is less certain about her future in front of the camera. There have been reports that Jolie, currently the highest-paid actress in Hollywood, is thinking of retiring from thesping. “I’ll do a few more,” she says slyly. “I’m about to direct something with Brad and myself, in fact.” That film, “By the Sea,” is currently being shot in Malta, and little is known about the plot other than it features Jolie and Pitt as a married couple.

She readily admits that directing is her first love. “I’m happier when I get to put a camera on another actor and watch them do great work.”

Though critics and audiences will soon pass judgement on “Unbroken,” Jolie has already received a rave review from the one person who matters. The day before Zamperini went into ICU for the last time, Jolie brought her computer to the hospital, climbed onto his bed and screened a rough cut of the film. “We were able to show him his life just in time to let him see all that he had accomplished and reflect on all the people he’s loved and was about to reunite with in heaven.”

Jolie begins to tear up again. “It’s not about ego, he didn’t want to be famous. He wanted to make sure his message was clear. It’s why he did speaking engagements, it’s why he did his book. It’s why he tried to get a movie made for 57 years. Everybody who reads this book and knows his life feels very connected to this man.”