By MELENA RYZIK

SAN FRANCISCO - The code word was “chill.” That’s what the crew with Shepard Fairey, the cult graphic artist known for his screen prints and stickers of the wrestler Andre the Giant, had been instructed to say if a police car rolled by as Mr. Fairey was pasting up posters one recent night here, illegally tagging warehouse walls and empty billboards with his black-andwhite images. Then Mr. Fairey and his helpers would know to run, to avoid yet another arrest.
But the law is not much of a deterrent for a self-styled populist artist. Mr. Fairey had already spent nearly a week attacking the city’s streets. By midnight he and his crew of a half-dozen 20-something guys, most employees at Obey Giant, his company in Los Angeles, had finished preparing for another all-night escapade at the White Walls Gallery here, where Mr. Fairey was displaying a solo show, “The Duality of Humanity.”
Dressed in torn jeans (Mr. Fairey) and hooded sweatshirts (everybody), they packed up supplies - buckets of paste, scissors, rope, video camera - and gathered the art: 3-meter-long photocopies of Mr. Fairey’s work, neatly snipped in half. Then they climbed into a rented minivan and went looking for real estate. They drove by one of Mr. Fairey’s Barack Obama posters, put up two nights before in a parking lot. It was already defaced - the “pe” in the slogan “Hope” had been torn off.
“Everything gets messed with,” Mr. Fairey said. “It’s just the nature of street art. You can’t be too precious about it.”
Mr. Fairey, a boyish 38, occupies a rare position for an artist. A star in the world of street art for nearly two decades , he has parlayed his stark imagery and guerrilla credibility into a successful design and marketing company with corporate clients like Pepsi. His “Obey” images and slogans appear on T-shirts sold at Urban Outfitters, and he has created logos for icons like Kobe Bryant.
Mr. Fairey draws scorn from underground artists who think he’s too marketable and critics who say he’s too dilulted. Benjamin Genocchio wrote in The New York Times that Mr. Fairey’s imagery “comes off as generic.”
Andrew Michael Ford, the director of Ad Hoc Art, a Brooklyn gallery that specializes in pieces by street artists, said, “People will say he’s doing something that seems very commercial.”
Through it all he has continued scaling fences to put up his purposefully simplistic, propagandistic images . This despite changes in his health (he is diabetic, and wears an insulin drip under his shirt), family status - he is married with two young daughters - and the continued arrests. Because the charge usually amounts to a misdemeanor, Mr. Fairey typically pleads guilty and pays a fine.
“My time’s too valuable to go back to court and fight,” he said. A child of the punk skateboard scene, Mr. Fairey said he considers the Sex Pistols role models. Being called a commercial sellout can hurt. Still, he’s not bitter.
“I hated being under anyone’s thumb when I was younger and now I’m not, through my art,” he said.
He added, “This ability to make things creatively on my own terms that then found an audience and sold - I’ve sort of made my dream come true.”