"The fact that a woman was at the center of it all was really shocking to me," Chastain said.
The movie is based on real events surrounding the decade-long hunt and the eventual capture and death of bin Laden.
"Maya is based on a real woman in the CIA, and she can't take credit for what she's done because she's undercover, and she's still working undercover," Chastain said. "In a way, making this movie is like acknowledging the sacrifices she's made and thanking her for what she's done. She worked for a decade, she gave up so much. She basically became a servant to her work."
Chastain spent months getting under the skin of this driven, focused CIA agent. She discovered she shared one trait with her on-screen alter ego.
"The similarity is we both love our work. I love my job just as much as Maya did. However, I don't get lost in my job," she said.
Chastain said there were more difference than similarities between herself and her character.
"I'm playing a woman who's trained to be unemotional and analytically precise," she said. "My whole career, my whole life, I've been trained to be emotional. I'm super sensitive; I'm a little flower child who grew up in Northern California."
But this hip little flower child has seen her career blossom in the past few years. With one Oscar nomination under her belt for last year's drama "The Help," she's on the road to more attention this awards season thanks to "Zero Dark Thirty."
"It's a feast for me. I mean, right now, it's like an embarrassment of riches," Chastain said. "My whole life, I've wanted to be an actor. I've always wanted to work with people like Kathryn Bigelow."
"Zero Dark Thirty" is rated R and opened in theaters Wednesday. It runs about two-and-a-half hours.