In January, 2007, a San Francisco magazine published a photo of a young man, his face half-obscured, under the headline "Guess Who's Reading The Nob Hill Gazette?" Tall, trim, and blue-eyed, he looked like a more earnest version of Luke Wilson. He may not be gracing the front page of The Washington Post yet, but 25 people guessed, correctly, that the mystery reader was Paul Pelosi, Jr. One of them was his sister Christine. He has three others, including the documentary filmmaker Alexandra Pelosi. His cousin is Gavin Newsom, the mayor of San Francisco. His father is Paul Pelosi, Sr., the investor, and his mother (you might have guessed) is Nancy Pelosi, the recently ascended speaker of the House. If the Pelosis are America's new political dynasty, then Paul Jr. is its rising prince.

Lolla-Pelosi aside, Pelosi tries to keep a low profile. At 38, he doesn't drink, works out regularly at the Olympic Club, and, unless business calls, which it does increasingly, sticks close to home. His axis of leisure comprises San Francisco (hometown), Napa (the family retreat), and Tahoe (where skiing and jigsaw puzzles are to the Pelosi clan what touch football was to the Kennedys).

But lately, as president of San Francisco's Commission on the Environment, a position he was appointed to in 2003 by then mayor Willie Brown, Pelosi has been logging even more miles than he does in marathons. "If we think there's an environmental hazard that can be prevented, then we don't wait for that risk to emerge," he said recently over breakfast at a Greenwich Village café. "I'm a momentum person," he went on, ordering a breakfast of iced tea ("It's good to stay hydrated") and a three-egg omelet, which, coming from the food-is-strictly-fuel school of consumption, he deemed paltry. "If I was at home, I'd have six eggs," he said. "It's like a rocket ship—you want to have electricity in your veins." Pelosi—"Paulie" to the family—may not be a natural-born nomad but, materially speaking, he lives like one: specifically, in an apartment in San Francisco's Marina district, where he abstains from using heat or air conditioning and doesn't wash his clothes during peak energy consumption hours. He usually takes the electric bus, but when he does drive, it's a Smart car, a hand-me-down from Mom and Dad. The Commission on the Environment has no legislative power, but it recommends policy to area lawmakers, so Pelosi, who has both a J.D. and an M.B.A. from Georgetown, believes in leading by example.