If all the recent hype, the adulation, the Emmy nomination and the breathless encomiums from the fashion flock have gone to the actor’s head, he does a credible job of concealing it. “The deadly thing in my job is to attach too much meaning to everything,” said Mr. Driver, who in person is thoughtful and unnervingly sincere, and smart enough to take a gimlet-eyed view of the overnight stardom that took him a decade to achieve. “You have to have a sense of humor about yourself.”

He was so nonchalant about losing the Emmy award for best supporting actor in a series to Tony Hale of “Veep” that Ms. Dunham said she was inspired to tell him he had been robbed.

“I was, like, you were ripped off, but Adam was like Adam,” she said, averring that he didn’t care whether or not he took home a gold statuette of a winged angel supporting the globe — or, anyway, unprintable words to that effect.

This was on a cold mid-autumn morning. Mr. Driver was hunched over a bowl of black coffee. Hours earlier at home with his wife, Joanne Tucker, whom he wed this year, he had eaten his customary paleo-diet morning repast of six eggs with four of the yolks tossed out. He no longer consumes a whole chicken for lunch every day, as he once did. Even a culinary cave man has his limits.

With a day of work left on Mr. Baumbach’s movie, he was taking a rare break from a schedule that will see him moving from one film set to another consecutively for the foreseeable future.

“I’m definitely trying to figure this all out as I go along, how to craft a career,” he said. “As things get bigger, I have days of depression, sitting in the house and wondering ‘What are you doing? Is it even relevant?’ ”