On the over 100-mile journey to Bethlehem from Nazareth, Joseph leads a donkey carrying a pregnant Mary across narrow paths along steep, rocky mountains and desert terrain, with little more than bread and water to eat.

Actor Oscar Isaac, who plays Joseph in “The Nativity Story” movie opening in theatres worldwide Dec. 1, told of his own journey in making the movie to Atlanta media at the Ritz Carlton Buckhead on Nov. 14.

The movie, which seeks to flesh out the sparse details of the birth of the Savior described in Matthew and Luke, Gospels written about 40 years after Jesus’ death, is also embroidered with apocryphal tradition and the filmmaker’s imaginative inspiration.

Isaac recounted the filming of one scene in the wilderness of Morocco alongside Academy Award nominee Keisha Castle-Hughes, who plays Mary in the movie.

“It’s dusk and right in front of me are the Atlas Mountains and the full moon starts coming up over it and it was just stunning. Joseph was asking for a sign and for him one doesn’t come, but for us there was this big sign. There’s this mountain, and the moon comes up, and I’m thinking ‘wow, what am I doing here? This is amazing.’ I’m standing in these sandals and portraying this man. … That was definitely a moment that perhaps struck me in a spiritual way.”

Isaac only found the word “righteous” in the Bible to describe Joseph, but moved beyond the icon to develop a flesh and blood character as he learned about the context of agrarian village life as a first-century Jewish carpenter. He also contemplated how Joseph stayed with Mary, although she didn’t carry his child, and participated in God’s plan for salvation. To prepare for his part the actor studied the Song of Solomon and other Scripture to understand the biblical concept of love, where he found inspiration for Joseph and his way of life.

“Any actor worth his salt that dives into a role takes something away from it. … It made me re-look at things. … Being raised (as a Christian) you kind of go on your journey and kind of question like Joseph does,” said the 27-year-old. “He was completely, utterly in love with her, but it was a selfless love, a humble love, that love from Corinthians, an agape love. That really struck me and how the entire story is about humility. It’s not the powerful and the proud who are exalted but the meek and humble. And I think that is a really powerful message. It’s not just information to let us know how Jesus came to earth. You really realize it cost these people something; there was a lot of sacrifice when that happened.”

The film has been screened at the Vatican and for Catholic leadership around the country. It was written by practicing Christian Mike Rich, who also wrote films including “Finding Forrester” and “The Rookie.” The film, a New Line Cinema presentation of Temple Hill Production, was directed by Catherine Hardwicke, who was raised Presbyterian. The film’s actors, many virtually unknown, hail from Trinidad, Iran, New Zealand, Guatemala, Cameroon, England, Jordan, Sudan, France and Italy.

An easy-going actor born in Guatemala and raised in Miami, Isaac has a swarthy complexion, wavy black hair and a sinewy build. Wearing tan plaid pants, chocolate high-top tennis shoes and a navy cardigan, he had both a soulful and boyish presence as he talked about his love of the craft he’s embraced since childhood.

As a child he played a shepherd in a Nativity play. “At that point my mom just kind of pushed me up there.” In the fifth grade he wrote the script and played a platypus in the story of Noah’s Ark. “(It was) just a fun little musical, but from that point on I just loved expressing myself.”

The big-screen newcomer graduated from the Julliard School in New York last year and learned of the movie. He initially questioned how an entire movie could be made from a few chapters from the Bible (“how much Spielberg can you put into it?”), but as he studied the script he was struck by the drama of the Christmas story seen in the hardship the couple faced in saying yes to God.

“I never understood that it was actually a very dramatic story of life and death situations for those people. So I thought that was really interesting and also, as a character study, Joseph is a fascinating guy and had to work through a lot of issues—the simple idea of having to share the woman you love with God. That’s a weird thing to have to comprehend,” he said.

After being approved for production in December 2005, the 93-minute film took two months to shoot amid the rolling green hills, protruding limestone rocks and olive groves of the ancient town of Matera in southern Italy where “The Passion of the Christ” was also filmed.

Villages then were always centered around a well so the movie’s art department laid out a city built upon that principle and positioned nearby other community buildings such as the olive press, wine press and synagogue. Houses were positioned up the hill, as the town would naturally have expanded upward away from the flat lands that would have been used for wheat and grape fields. They built the set next to a series of caves that have been inhabited for nearly 8,000 years. These caves—where homes, restaurants and churches are built into the bedrock of the mountain—became the old streets of Jerusalem.

They also filmed in Ourzazate, Morocco, where the art department built the village of Mary’s cousin, Elizabeth, played by Academy Award nominee Shohreh Aghdashloo. Local crews built the houses “first-century style” with thick walls made of mud from a river close by, floors of tamped earth and brick-baking furnaces. The Sahara Desert itself, with its 135-degree midday heat, was used for the beginning of the Magi’s journey from Persia and also the Holy Family’s escape.

Isaac attended a month of “Bible boot camp” in Italy where cast members learned how to bake bread, milk goats, press olive oil, plant wheat and use ancient tools. He learned masonry using first-century tools and built the stone house he constructs in the film, which left his hands bruised and calloused, and learned to move in a taxed way that reflected a life of survival. As the lifespan back then was about 40 to 45 years, Isaac envisioned Joseph as about 23.

“The staff I used in the film, I made it myself. I took it back to New York and use it on the subway,” he said with a smile.

The actor envisioned Joseph’s reaction when he initially sees Mary pregnant as similar to how Jesus addressed Mary Magdalene with love, he said.

“‘If I have the faith to move mountains but I don’t have love, I have nothing.’ So I think that’s one of the great messages of the film, that if you work out of love and humility, faith is born out of that. The fact that he treated Mary with love and humility and didn’t stone her, that’s what opened his heart for God to speak to him.”

He believes it’s “an incredibly reverential script” as it uses Scripture throughout, from Mary’s Magnificat to Christ’s birth in a cave-like stable grotto amidst sheep and goats.

Isaac noted how the actress Castle-Hughes drew inspiration from the line from the Bible that Mary “pondered (these things) in her heart,” and her character seems to soul search throughout the movie. After she was cast he viewed her Academy Award-nominated performance at 12 in “Whale Rider” and was impressed by her acting ability.

“I was blown away. It’s as if she forgets she’s in a movie. It’s as if the cameras weren’t around and that’s actually the place that every actor hopes to get to, a place where they can really disappear into who they are. She, in some mysterious way, figured out how to do it.”

The film also foreshadows elements in Christ’s ministry, such as how Joseph expresses anger over merchants in the Temple courtyard. Another is Mary washing Joseph’s tired feet.

“Maybe Jesus does learn some things from his father,” said Isaac.

His acting approach for “Nativity Story” was to bring himself and his experiences into the role but to become Joseph. It was “learning how to be a young Jewish man in the first century and his relation to God and the land. That was integral to how they identified themselves throughout.”

He hoped to move beyond Joseph as “just a walking icon” and “to show the audience he is like us and he does feel the things we feel—anger, hurt, betrayal, love, desire, jealousy, all these things.”

“He works through them and so by the end, because of his actions and because you can see it really cost him something, you can say that man is a righteous man, a good man.”

In a press release, writer Rich said that during the 2004 Christmas season he began to consider how Mary and Joseph got to Bethlehem, what kind of people they were, and what challenges they likely faced. He contacted his agent and set out to research who they were and what they might have thought.

“As a person of faith myself, and as a storyteller, those were compelling questions. … I found myself drawn to the amazing choices and decisions that Mary and Joseph made, relying solely on their faith in God and each other,” he said.

In research “what I had to do was really delve into the socio-political and cultural dynamics of the time. The research actually gave me quite a bit to work from, because it showed the dynamics, and from there you could get a real feeling as to what Mary was dealing with.”

Last year his father died and he felt spiritually and emotionally compelled to “tackle something.”

“And so, shortly after Thanksgiving, I wrote the first draft, surrounding myself with music and the Christmas carols. It really was a very spiritual experience. It was a joy to write, not because it was a huge epic, event-based story, but because it was just the opposite: a personal, intimate story of two ordinary people carrying out this absolutely extraordinary mission.”

Isaac is indeed grateful to tell the story of Christ’s coming to save all peoples and nations. Among his other projects, he will appear next year in “The Half Life of Timofey Berezin,” a dark comedy produced by Steven Soderbergh and George Clooney that takes place after the fall of the Soviet Union. His other film credits include “Guerrilla,” opposite Benecio del Toro, produced by Soderbergh. He has acted on stage including for the New York Public Theatre’s Shakespeare in the Park program. He writes and performs music with his band and resides in New York.

His favorite films are from the ‘70s, including “Midnight Cowboy” with Dustin Hoffman, and above all, Al Pacino in “Dog Day Afternoon,” “which is like listening to a piece of Bach—that film competes with Julliard in how I learned to act.”

He admires dedicated actors not driven by ego, but “who really pour themselves into it, that really try to contribute to the art form.” He regrets the rise of “the cult of celebrity,” in which artistic merit is often overshadowed, and is eager to make his unique contribution to the industry.

“I’m just excited to tell really important stories.”