For the next decade, Paul did what young, struggling actors do: He hustled, he auditioned, he waited, hoping for something big. "My first gig was a Corn Pops commercial," he says. "I did the first Vanilla Coke campaign. A Juicy Fruit commercial paid my bills for years." He appeared on 26 different TV shows as a day player, everything from Melrose Place to The X-Files to ER, before finally landing a semi-regular role as Amanda Seyfried's husband on HBO's Big Love in 2007—a monogamous foil to all the polygamy, though still at day-player rates ($600 per episode). "That's when I started doing stuff on a regular basis that I was really, really proud of," Paul says. Breaking Bad began shooting the next year.

At first Paul couldn't get an audition, and once he finally did, the executives producing the show at AMC and Sony had their doubts. "They thought I was too old," Paul says. "They thought he might be too handsome," Vince Gilligan says. But Gilligan insisted on casting him. "Ultimately," Gilligan says, "Aaron's talent and charisma won them over." Paul credits Gilligan with giving him the role of a lifetime. "I don't know if a role that detailed is ever going to come to me again," he says. Still, Jesse Pinkman was originally meant to die in some undecided way during the show's first season. "My spine started to hurt when they told me that," Paul says. His gripping, grueling, bug-eyed, and adrenalized performance, however—coupled with his extraordinary onscreen chemistry with his costar Bryan Cranston—made Jesse essential. "I didn't foresee what the character would become at first," Gilligan says. "Over the years, Jesse became more likable than I originally intended, because Aaron himself is so easy to relate to. He deepened my understanding of the character, and that deepened the meaning of the show."

When Paul speaks about Breaking Bad, a line of conversation he weaves in and out of through the course of our 10-hour day, he does so with both surprising detachment and intimacy. "I don't think I'm ready to move on yet," he says. But there's also a sense that Paul can hardly believe he got to do the show at all. "I think he's always aware of his good fortune," Cranston says. "He's a guy who's very capable of counting his blessings, a very sweet man. Much sweeter than I am. And, also, a damn fine actor."

Despite his easygoing, indie-folk ways, Paul possesses such intense empathy for Jesse that he in fact feels as if he's gone through everything Jesse has: waking up next to a dead, overdosed girlfriend; seeing another one murdered in front of his eyes; pulling the trigger on an innocent man; being shackled, beaten, hunted; feeling terminally alone and serially betrayed. "Aaron's willing to pay for his character's actions," Cranston says. "He's willing to sit in that vastness of uncomfortability. He stays in it, wallows, ruminates, paces around set, screaming in the corner of the room." Paul admits he even dreams as Jesse Pinkman and not as himself.

And when it came down to deciding Jesse's ultimate fate, Paul couldn't help but weigh in. "I wrote an e-mail to Vince before we started shooting the final eight episodes—a plea for Jesse, a love letter," he says. "I never give my two cents when it comes to Breaking Bad, because why would I? I'm just the actor, and what they're doing is perfect, you know? But I just felt like I would always regret it if I didn't at least throw them a pitch on how I wanted Jesse to go out. So I gave a few different ideas of how I thought he would kill himself. I didn't want anybody else taking his life." Paul heads into one of the Alcazaba's fortified passages. "The letter was awful," he says, seemingly rattled at the idea of Jesse's dying and, also, at having had a hand in killing off an alter ego he can scarcely separate himself from. "It was very morbid, and I'm so happy they didn't listen. I'd rather Jesse just kind of ride off into the sunset like he did."