For those inclined to hate Pete Wentz­—and there seem to be a lot of you out there­—a word of advice: Don't ever meet him. It's 11 P.M. when the Fall Out Boy bassist and lyricist­—as famous for his branding efforts, cosmetic proclivities, and tabloid-princess wife as for his music­—strides into a nearly empty restaurant in Barcelona, wearing one of his countless hoodies (this one from his clothing line, Clandestine Industries). "Dude," he says, offering his hand. He stands five feet seven, with a top-heavy bobble-head quality, and exudes so much boyish charm you're almost tempted to lick a palm and smooth his hair out of his eyes.

Wentz has just arrived from Los Angeles, and he's tired. But then, he's always sleep-deprived, he says, despite popping Ambien like Tropical Skittles. He's got a lot going on these days. In addition to overseeing Clandestine Industries, he's keeping tabs on his record label, Decaydance, which he runs like a sort of promotional puppy pile, in which the bands­—including Panic at the Disco, Gym Class Heroes, and the Academy Is ...—share a management team, tour together, and turn up as guests on each other's tracks and videos.

He's also prepping for a second season of FNMTV, the weekly music-video show he hosts, and getting set to unveil the latest outpost of his bar, Angels & Kings, the would-be Planet Hollywood for the emo crowd. Though the first A&K, which opened in New York in 2007, was billed as a gritty clubhouse for Wentz and his friends (a Chicago branch opened this summer), this location­—just off the pool deck in the brand-new luxury ME Barcelona hotel­—is an uncharacteristically upscale affair.

Meanwhile, on December 16, Fall Out Boy­—the less celebrated members of which are guitarist Joe Trohman, drummer Andy Hurley, and singer-composer Patrick Stump­—will release Folie à Deux, a collection of attention-deficit genre mash-ups, featuring cameos by Lil Wayne, Debbie Harry, and Elvis Costello.

And then there's the ultimate brand extension, the one guaranteed to propel Wentz into a whole new sphere of exposure: Bronx Mowgli Wentz, the son he and his wife, Ashlee Simpson, welcomed into the world on November 20. When Wentz found out Simpson was pregnant, he was in Chile with Fall Out Boy, preparing to play a show in nearby Antarctica. "I was like, 'Oh my God, this might be the worst possible time to have this conversation,'" he says. Perhaps to make sure the news had sunk in, Simpson promptly e-mailed a snapshot of the pregnancy test. (Us Weekly, eat your heart out). "I was definitely scared," Wentz says, "just thinking, This is something that's going to exist for the rest of your life and you can't fuck it up."