Except for 2009’s action-heavy “G.I. Joe: The Rise of Cobra,” Sienna Miller’s acting roles have one thing in common. She’s drawn to parts that feature complicated characters, whether it’s a part based on a real person such as playing Tippi Hedren in “The Girl,” or a fictional role, as is the case of her new film, “American Woman.”

Miller’s latest acting journey into the highs and lows of being human gives her a broad spectrum of emotions to play.At the start of the film, Deb Callahan (Miller) is an emotionally jumbled mother and grandmother whose life seems to be an endless stream of bad decisions. That changes when her teenage daughter mysteriously disappears and Deb is left to raise her young grandson while facing her own pain.

“American Woman” gave Miller the opportunity to play a character with a huge emotional arc. Deb starts out as one kind of person but makes a complete transformation by the end of the movie. It was the strength and the frailty Deb shows that made Miller interested in the project.

“The resilience of Deb is something that really appealed to me. This film is about the resilience and triumph of the human spirit,” Miller says. “Seeing a woman get knocked down and get back up again is just a beautiful thing to see on film. There is a fragility to her, but I loved how she sort of tried to hide it.

“It felt like an authentic look at an American woman. It felt like a real story about family, about love, about strength. It is a real gift as an actor to get a gift like that.”

Miller embraced that Deb is flawed, funny and messy but is growing up. She believes everybody knows a Deb.

And she’s quick to stress while the movie includes the major element of the disappearance of Deb’s daughter and the aftermath, this is a movie that has much more hope in it than one might expect. That hope in the time of a great crisis is what Miller saw when she talked to those who went through this kind of event. She wanted to reflect the strength and attitude they all showed of being able to get up and go on the next day.

Once Miller committed to the role, she dove deep into the character. She was hesitant when she was offered the role because there were some dark moments. But her concerns vanished when she met director Jake Scott.

“I knew he was the perfect person to direct the film. He is incredibly sensitive, incredibly loving,” Miller says. “He experienced every step of this film with me. Without that support I would have fallen apart making this.”

“American Woman” is the latest role for Miller where she has focused on playing strong characters. Other strong character credits include “Layer Cake,” “Factory Girl,” “Alfie,” “Stardust” and “Mississippi Grind.” Miller has been able to find the kind of multifaceted type of roles even when taking on parts based on real people such as in “Foxcatcher,” “American Sniper,” “The Lost City of Z” and the upcoming Showtime series “The Loudest Voice.”

Miller has a slightly different approach to playing roles based on real people but eventually the process gets down to finding the elements that make the role interesting to her and the audience.

“If you play somebody who is real, there is a lot more research available to you. I love doing that,” Miller says. “But, when you are doing something fictional, you have to invent that history for yourself. Ultimately, it is an intuitive response. You get a sense of someone and then you do all the work you can do.

“In ‘American Woman,’ I had to spend a lot of time thinking about what it would be like which was dark and hard and sad. But, I also think she is relatable and I want to play people who are relatable who represent real women.”