Cristiana Dell’Anna, who stars as Sister Frances Xavier Cabrini in this week’s aptly named biopic “Cabrini,” knows when creating a character you never start with the saint.

Which is what this nun is. In 1946, nearly 30 years after her death, this Italian-born nun became the first American citizen canonized by the Roman Catholic Church.

She had overcome sizable obstacles in her mission to help the poor and homeless: Notably rampant early 20th century anti-Italian bigotry and blatant sexism, whether dealing with an amused Pope Leo XIII (Giancarlo Gianini), St. Patrick Cathedral’s combative cardinal (David Morse) or New York’s unapologetic mob boss of a mayor (John Lithgow).

As founder of the Missionary Sisters of the Sacred Heart of Jesus, her legacy embraces a worldwide network of hospitals and orphanages.

“You never start from the holiness of the character because that’s something that comes afterwards. It’s something that is determined by the actions they do,” Dell’Anna, 38, said in a Zoom interview.

“In order to be faithful to the character, you have to find the humanity, the connections with who you’re portraying.

“I wanted to see her as a woman, first of all. To do that, I had to find the things that she had in common with me. Even when I heard she was a nun — I was a little put off by it. You always have the prejudice it might be a limiting character, only a religious one.

“But actually, she was so much more. While researching her life and the legacy she left behind, I immediately realized this was a once in a lifetime opportunity. I couldn’t miss it. I had to play her.

“She’s just done so much for the world — and she’s so interesting! A frail woman diagnosed with tuberculosis since she was a little kid? Who then became, yes, the first American saint?

“She helped immigrants. She was a businesswoman, a great feminist, as well as pioneer. She had so many wonderful characteristic but she had her weaknesses too. At times I found her contradicting herself.

“Because the Pope himself at some point asks her, ‘I can never see when your ambition ends and your faith begins.’”

Dell’Anna, born in Naples, has had an international film career. Being Italian did she feel a responsibility she wouldn’t normally feel with other roles?

“It fills you with pride to play a woman who impacted American history and had Italian origins. But the responsibility was more towards being faithful to who she was. To do justice to what she achieved.

“But if she hadn’t been Italian, I don’t think I would have got the role.”

“Cabrini” opens in theaters March 8