In making “Reservation Road,” director Terry George often went for an improvisational approach using handheld cameras. Connelly, playing a bereaved mother, enjoyed the challenge.

“Terry wants to get what’s going to happen in that moment. That is his priority, and you feel it,” says Connelly. “To him, that’s more important than, ‘Oh, I thought it was going to go this way in my head. Let me get the actors to do that.’ ”

Although only 37, Connelly has already been in front of the camera for more than 25 years. “I think I was 11 when we filmed ‘Once Upon a Time in America,’ ” she says of Sergio Leone’s 1984 gangster epic. “I didn’t see myself as a child actor. I was just a kid who had made a movie.”

That changed with Keith Gordon’s 2000 feature, “Waking the Dead.” “This was the first time that I felt like I brought all of my attention, all my resources, for better or worse, with me to work. I’m not saying it was the best performance, but it meant a lot to me.”

Connelly’s M.O.: “What I look for, what I hope for, are the ones that are very clear, like ‘Reservation Road.’ But it doesn’t happen that often. More often you may be thinking, ‘Well, does it work? Does it not work? It’s kind of good or the part is good, but I don’t know if it falls apart.’ “