Updated February 02, 2015 12:00 PM

1. “I’m a lucky girl,” Chastain (in an Elie Saab gown at the Cannes Film Festival last year) says of working with stylist Elizabeth Stewart.

2. “I didn’t want to do over-the-top ‘tawk,’ ” she says of her New York accent in Violent Year (with David Oyelowo).

3. Boyfriend de Preposulo “has a passion for the arts,” she says.

She already has two Oscar nominations to her name and just missed getting a third this year. But Jessica Chastain is still a bit mystified by the whole awards thing. “It’s a formula I don’t understand,” she says, chatting a few weeks before the nominations. “Some of my favorite performances don’t get acknowledged. Marion Cotillard in Rust and Bone is perfection. Shailene Woodley in The Descendants. Isabelle Huppert has never been nominated; she’s my favorite actress in the world!” Still, “it’s fun to be part of the conversation.”

She always is. Chastain, 37, who earned Oscar nods for The Help and Zero Dark Thirty, starred in four movies last year, including the sci-fi blockbuster Interstellar and the drama A Most Violent Year, just opening in wide release. “I always want to do things I haven’t done before,” she says. With tragedy in her past, she gets strength from her family and boyfriend, an Italian count.

Her Bad-Girl Move

She’s played smart, tough women before, but never one with the edge of the Mob boss’s daughter she portrays in Violent Year, which earned her a Golden Globe nod. In one memorable scene she shows an investigator who’s boss with the toss of a cigarette. “That was a Chastain invention,” she says. “I had no idea people would be coming up to me and flicking a cigarette and quoting my line, ‘This was very disrespectful.’ It’s very cool.”

Her Difficult Past

The oldest in a large family raised in Sacramento by her chef mom and firefighter stepdad, Chastain has never spoken of her biological father, a musician who died in 2013. She dropped out of high school and later earned her GED before landing a scholarship to Juilliard. Then in 2003 tragedy struck when her younger sister Juliet committed suicide at age 24. “The focus of my life changed,” she told ENTERTAINMENT WEEKLY. “I didn’t care about being the best; I just wanted all the people in my life to know how important they were.” Holidays are major; two years ago she surprised her family at Christmas with a trip to Disney World, “my favorite vacation ever.” With them, “I can just sit there and laugh. I like that I can just be with everyone and not have to take a role.”

Her Love Life

She’s been dating Italian fashion executive Gian Luca Passi de Preposulo since 2012 and “everything is fantastic,” she says. They’re not engaged. “I’m not quite sure of what I want in my life, and who knows if marriage is part of it, so to me marriage is not an important thing.” As for motherhood, she says she recently told her brother Will, who is in the Army, that she hopes they can institute an annual holiday get-together. “I said, ‘Someday you’re going to have children, someday I’m going to have children, and I want our children to know each other,’ ” she recalls. “If we can spend a week together every year wherever we are, how beautiful would that be?”