If the thought keeps him up at night, he doesn't show it. "I would have been perfectly happy, I think, continuing my career the way it was. Just being that guy in shows. I probably could have had a very nice career doing that. And still may, honestly. The big book ain't written yet."

•••

"Sit in Matt's chair, he's never here," Jon hamm says, pointing to Mad Men creator Matthew Weiner's director's chair.

It's a joke, of course, but it's disconcerting on a few levels. First there's the fact that Weiner is the famously hands-on guiding force of the show, so it seems wrong to touch his chair. But the thing that's really making my head tingle is the total transformation of the guy I'd driven around with the day before. He's standing on the set of Sterling Cooper Draper Pryce in full Don Draper drag. Hair slicked back, gray suit on, tie bar in place, pack of fake Lucky Strikes at the ready. The metamorphosis is striking and complete, down to the way he walks, his body language, eye contact. It occurs to me that this is why Weiner keeps journalists off his sets: so nobody will realize that the reason his cast is so good is that the "actors" are actually split-personality cases who've fully inhabited their roles.

"One of the greatest pleasures of the job," Weiner says, "has been to see Jon create the character of Don Draper. He's smart, deep, and a natural leader. I can't imagine making the show without him."

Elisabeth Moss, who plays Peggy, says the whole cast considers Hamm "the leader of our little gang. We do defer to him. If there's something that we need to fix, we go to Jon.

"It's funny," she adds. "There definitely are a lot of similarities between how Jon and I get along and the relationship between Don and Peggy. But Jon doesn't yell at me as much—thank God. That would be a bit rough."

One odd thing about delayed recognition for an actor is that not everyone who actually knows you knows you can actually act.

"It's funny," Hamm says. "You realize certain people didn't know I was funny because they only saw me through Mad Men—or only knew me as me and never thought I could do Mad Men. Sarah Silverman said, 'Hammy, you're good. I had no idea!'" Silverman met Hamm in 2000 through a group of friends, including Rudd, Adam Scott, and Jon Schroeder, who all played poker together. "When I tuned in to Mad Men, I couldn't believe he was this smoldering, brooding sexual man," Silverman says. "I was like, 'Oh my God—that's Hamm!' To me, he's just this super-silly idiot.

"He's one of the very few actors who are comedian-compatible," she continues. "Not to sound elitist—I just mean he's one of us misfit toys." Silverman proves this by pointing out her minor but important contribution to Hamm's career. "Before Mad Men, he played a cable guy on my show on Comedy Central. He had one scene. On his jacket, just small enough that you can't read it on TV, it says: EATIN' ALL THE PUSSY SINCE '92."

What this late-period success means for Hamm is access. "You get to sit at the big table with the big boys and hang out," Hamm says. "Sean Penn and Meryl Streep are having a conversation, and you're standing next to them, and they stop and turn to you and say, 'Oh God, we love your show.' Yeah, that wasn't happening with my work in What About Brian."

I ask him if he feels lucky that his overnight success took as long as it did. "Absolutely, I don't know how the Twilight kids or Miley Cyrus or whoever handle it. You fuck up, make one bad decision, and people in Thailand Twitter about it." Hamm's mostly left alone, he says: "I'm old, I'm boring. I usually just duck the paparazzi. It's literally someone waiting for you to pick your nose or scratch yourself. I'm sorry, I scratched my balls—who doesn't do that? You're really going to run that story? What the fuck?! Everyone has picked their nose at one point in their life too."