In Won’t Back Down, which opens Friday, Viola Davis plays a discouraged teacher who rediscovers her spark for education by joining forces with a working-class mother ( Maggie Gyllenhaal) fighting to take over a failing inner-city school.

The film, which is inspired by real events, is already stirring controversy and being slammed by teacher unions, which object to how they’re portrayed.

Davis is someone who’s appeared in several movies that touch on hot-button topics.

“When you create stories where that’s the background, the characters will absolutely be interesting,” she told the Detroit Free Press in a recent phone interview. “If you start with that palette, then what will grow out of it is really substantial characters fighting and slaying big dragons, and you always want that as an actor.”

Davis, however, isn’t interested in playing heroes without flaws. In this movie, she’s a woman who’s struggling with a divorce and raising a son with learning difficulties as well as coping with career burnout.

“I don’t think it would be easy to come in and say, ‘Hey, let’s start a school.’ I do think that comes at a cost. That’s what life is about,” she says of her character. But “the more she stepped toward the challenge, the more she began to come to life.”

Although Davis, 47, didn’t take home the Oscar for The Help earlier this year, she was a winner in every other sense. The Tony-winner who’d spent more than a decade as a character actress — and who got a best supporting Oscar nod for 2008’s Doubt — emerged from awards season as a full-fledged movie star.

Davis brings empathy and compassion to her portrayals of private, often emotionally guarded women who reveal themselves to be anything but ordinary.

Davis says she’s interested in characters who are going through the motions of life, and in exploring what it would take to wake them up.

“I do believe many of us catapult ourselves to the grave never having tapped in to what’s extraordinary about ourselves,” she muses.