Amy Ryan in 'Gone Baby Gone'

Not long ago, Amy Ryan earned a nickname from her friends, thanks to all the gut-wrenching dramatic roles she was taking on. "They started calling me 'Crying Ryan,' because every time they saw me on screen, I was breaking down all the time. I made a professional goal that for one year I wouldn't cry in a role," she says, exposing a wide grin audiences rarely get to see.

And how long did that last? "About two months," she admits, laughing.

There's something about Ryan's exquisite, pale face that just looks good anguished. It has served her well on the HBO series "The Wire," on which she plays a good cop in over her head. On stage she earned a Tony nomination in 2000 for her role in "Uncle Vanya" and in 2005 for "A Streetcar Named Desire." In 2006 she took on the role of a mother grieving over the death of her young son in the West Coast premiere of "Rabbit Hole."

And now there's "Gone Baby Gone," co-written and directed by Ben Affleck, based on the novel by Dennis Lehane. In the film, Ryan plays Helene McCready, the mother of a young girl who disappears mysteriously. Though the tight-knit Boston community binds together to help her, Helene is hardly the film's heroine: She's a drug addict who grossly neglects her daughter and might even be in on the kidnapping.

Ryan is literally unrecognizable as Helene. "That's what I wanted," she enthuses. "Ben said, 'I would love at the end of the day for people to ask me, 'Where did you find that local Boston actor?' I do prefer hiding away into characters rather than having the characters come to me. Most characters I play have better hair than my own, anyway."

Affleck knew he needed the right actor for Helene and says it was the most difficult role to cast. He was surprised an actor of Ryan's caliber would audition.

Their first meeting went well. "I read about four scenes, and Ben looked at me and said, 'My God, you are one nasty actress,'" Ryan recalls, laughing. "I said, 'I think that's the nicest thing anyone's ever said to me."

Also impressing Affleck: Ryan's dead-on accent. "I'm really, really finicky with Boston accents," says the director, who was raised in Massachusetts. "And she nailed it."

Ryan grew up in New York and attended the High School of the Performing Arts. Though she was accepted at New York University, she instead took the role of Daisy in a national tour of Neil Simon's "Biloxi Blues." From that point on, Ryan has supported herself as an actor.

Ryan is earning terrific notices for "Gone Baby Gone" but says she tries not to hear the buzz. "I've been in this long enough to take everything with a grain of salt," she notes. "But it struck me three weeks ago, riding the subway, that I would be bummed if I couldn't do that anymore -- because a lot of my continued education as an actor is people-watching, and if I couldn't do that anymore, I would be screwed. The flip of that is that you would have access to better scripts, stories, and writing. And that would be a thrill."