You know you have successfully reinvented your Hollywood career when the first question of every interview changes from "Why did you make that movie?" to "How did you make that movie?"

For your consideration: Ben Affleck, the 2012 version—an accomplished 40-year-old director of movies that please both critics and audiences, a dutiful father of three, and, not incidentally, an actor in ever-firmer command of his craft.

With his first two features behind the camera, Gone Baby Gone (2007) and The Town (2010), Affleck, who grew up in Cambridge, Massachusetts, mined the terrain of Baaahston bad guys and anti­heroes so skillfully that he probably could have kept working the genre for years. Instead, he chose to raise the stakes with Argo (opening October 12), a drama that retells a long-classified story from the Iran hostage crisis. In the film, Affleck plays a CIA agent who enlists a Hollywood producer (Alan Arkin) and a makeup artist (John Goodman) in a quixotic attempt to extract six American-embassy workers hidden in the Canadian ambassador's residence in Tehran by having them impersonate a film crew producing the cheesiest Star Wars rip-off never made. Argo is full of revelations, not the least of which is how deftly Affleck juggles backlot humor, suspense, and geopolitics while steeping the film in his love for the cinema of the 1970s, which he calls "the greatest era in American movies."

Appropriately, our interview begins in Burbank, California, on the Warner lot—not the part where rich producers have office bungalows but an old New York streetscape (complete with brownstone façades and alleys and stoplights) that's fallen into disuse. "These days it's mostly TV shows like Harry's Law that shoot here," Affleck says wistfully as a tour bus rounds the corner into view. The passing visitors show no signs of recognizing the star—not a surprise, since in tailored jeans, an untucked dark button-down, and the gray-flecked beard he grew for Argo, Affleck looks more like an exec or a crew member than "talent."

The bus disappears around a bend of the ersatz urban horizon. "I thought this would be a good place for us to talk," Affleck says, "because this is a studio movie. A real one. We shot part of the film right here on the backlot, which not that many movies do anymore." It's clear he's a long, long way from . . . well, you remember that stuff. He knows you do. And he's okay with it.

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DETAILS: Argo doesn't fit neatly into any genre. How did you manage to make a movie that's both a sharp comedy about the movie industry and also a complicated historical drama?

Ben Affleck: That was the toughest thing. I thought, "This is my third movie—I have confidence that I know how to shoot, I know good actors, and the script is good. The one thing for me to do is to deal with tone." And tone is really hard. When you get tone wrong, it's not like you can go reshoot it. You're just fucked. The movie's destroyed.

My big concern was that there's so much comedy, and if it became too slapstick or too goofy, suddenly you don't care about those people trapped in Iran, because you know they're going to get saved. I always said the joke is the first thing to go. If it borderline does anything wrong to the rest of what we're doing, it has to go, even if it's gut-busting.

After that, I just made sure that every moment felt real. I wanted these actors to feel that they were in this house in Tehran. So we went to all these cliché-Method lengths.

DETAILS: You had the six actors playing hostages live together while you were shooting in Istanbul, right?

Ben Affleck: On Pearl Harbor, they put us in with military guys for two weeks, and it was incredibly hard. But incredibly good for me as a person. I don't know how much it correlated to what happened in the movie, but I remembered that worked well. So I thought, "I'm gonna have them live in the house, and if nothing else, it'll give them something to say at the junket." And they stuck with it, the six of them—they kind of formed this unit, drinking together, running around Turkey. They had bonded.

DETAILS: What made you decide to star in Argo too?

Ben Affleck: I liked the idea of being in the movie, pushing it forward. As an actor, you can steer a scene in another direction by playing it a little differently. And honestly? I like being an actor, and I want to keep having a career. It'd be very easy for me to get lost in directing for a year and a half or two. It's a business with a very short memory.

DETAILS: But when you're acting in your own movie, don't you miss having a director to lean on?

Ben Affleck: Every single director-actor I talked to, from Warren Beatty to Clint Eastwood to George Clooney, said the biggest mistake they made is not shooting enough footage of themselves. You go back to the editing room and you have virtually nothing to work with. And you think, "I could've done better—a director would have pushed me to do more." So I just said, "Okay, I'll push myself to do more."