Together with his cousin, Dash started managing two groups called Future Sound and Original Flavor. Dash's uncle introduced them to Rodolfo Franklin, a.k.a. DJ Clark Kent, at Atlantic Records, who signed the groups. But according to Dash, the label failed to support them, so he started touring his acts on the East Coast with another artist Kent had introduced him to: a 24-year-old former Brooklyn drug dealer named Shawn Carter, who took the stage name Jay-Z. "He could rap fast, and his raps were witty and fresh," says Dash, still visibly impressed. "And everything he said was authentic. That made him better than . . . everyone."

But despite his wit and talent, no label would sign Jay-Z. At the time, West Coast gangster rap was ascendant, with its street rhymes about gunplay, murder, and crack. Jay-Z was playful and cocky, rapping about the hustler's good life and making bank: "You can't change a player's game in the ninth inning/ The chrome rim spinning keeps 'em grinning/ So I run way the fuck up in 'em/ And wrinkle they face like linen."

Dash paid out of his pocket to get Jay-Z in the studio. When they still couldn't get a record deal, they launched Roc-A-Fella Records with Burke, another street hustler, who was later convicted of drug trafficking. The combination of Dash's entrepreneurial bravura and Jay-Z's talent paid off. In 1996, they released Reasonable Doubt, which many critics still consider Jay-Z's finest work. Dash—bellicose and shrewd—struck uncompromising deals for himself and his partners. When they signed a distribution deal with Def Jam the following year, Dash insisted he, Jay, and Burke retain half-ownership of Roc-A-Fella and full title to Jay-Z's master recordings. "Damon was a leader and a visionary," says Def Jam's founder, Russell Simmons. "Without Damon, there would have been no Jay-Z or Kanye or Cam'ron and no Roc-A-Fella. What he did for Jay and everyone, he was selfless. He took the bullets."

But Dash wasn't satisfied with music's small profit margins. He wanted a lifestyle brand, "like Ralph Lauren," he says. His timing was perfect. Hip-hop artists had started to ask why they were shilling for these brands in their music videos—brands that were then bought by millions of fans—when they could be making their own clothes, vodkas, champagnes, and sneakers. So Dash started Rocawear, and each time Jay-Z wore a bomber coat, a warm-up jacket, or a snapback in a video, sales boomed. By 2003, Dash had landed Victoria Beckham as a model, putting her in satin jackets and high-riding booty shorts.

But Dash and Jay-Z's relationship soon began to fray. Word of his partner's volatile temper started reaching Jay. In an infamous YouTube video, Dash lashes out at a boardroom full of Def Jam brass for allegedly holding a meeting about Jay without inviting Dash. "Y'all should have called Damon Dash," he rants. "Y'all don't know shit about my culture."

"Damon was all creative aggravation, and he had to be when making Roc-A-Fella great," Simmons says. "It was a commitment not to compromise." It worked on the streets and in building a company, but not in a corporate workplace. "Damon was a bull in a china shop," Simmons says.

Dash says he was never cut out for that world—he wants to be a Richard Branson–type entrepreneur-cum-magnate, creating companies and getting other people to run them. He also heaps scorn on the Def Jam team that would later become Jay-Z's inner circle. "Those people are corny. You think I'm rolling to a club with Lyor Cohen or John Meneilly?" he says, referring to the former head of Island Def Jam and Jay's manager. "No disrespect to Jay—but every single person I see hanging around him is making money off him. They all conform so they can eat off of him."

By 2003, as Jay-Z talked about retiring after the release of The Black Album, Dash began turning his attention away from his star talent and best friend and toward his newer finds—Kanye, Cam'ron, Jim Jones, and Beanie Sigel. While Jay-Z was on vacation, Dash made Cam'ron and Sigel vice presidents of Roc-A-Fella. Dash was also using his own money (up to $6 million) as well as Rocawear's to launch a new fashion line, Rachel Roy. He had started dating Roy when she was a Rocawear intern and later married her, in 2005 (they divorced four years later, and they still control half of the brand).

Dash's overreaching ambitions and hot temper became too much for Jay-Z. In December 2004, he invited Dash to a sit-down at the restaurant Da Silvano in New York's Greenwich Village. They had already agreed to sell their remaining half of Roc-A-Fella and its roster of contracts, including Kanye's, to Def Jam for $10 million. But in a twist, Jay-Z announced he would become president of Def Jam, taking on a role that would seem, by right and reason, destined for the business-minded Dash, a role Jay-Z could not perform if Dash were in the picture. Jay-Z had one carrot to dangle in front of his old friend. He offered Dash the Roc-A-Fella name in exchange for turning over the rights to Reasonable Doubt, which Jay called "my baby." Dash refused. "Honestly, I didn't give a fuck," Dash says. "The whole thing was based on our friendship. He made it clear he didn't want me to be a part of Roc-A-Fella. I was like, 'A'ight.' Everything else was like, 'Go be you. You want to do this, do it.' He told me it was just business. He said that it was business. 'I want to look like a businessman, and I can't be a businessman around you.'"

• • •

Damon Dash's headquarters these days is his two-year-old Poppington art gallery on a grubby stretch of Orchard Street, among seafood wholesalers and cut-and-sew factories. It's not unusual to see workers on fourth-floor fire escapes across the street sending bags of cheaply made suits flying down a zip wire into the backs of waiting vans.

Before you even see the large Poppington neon sign above the door, you can smell pot smoke wafting down the block. One day in late November, a week or so after the Mercury Lounge show, the bottom floor of the 6,000-square-foot duplex is deserted. A few pieces of geometric acrylic artwork line the walls. An open loft overlooks the gallery, and a set of back stairs leads to it. Up here, Dash's crew is working or hanging out while the boss is getting his twice-weekly haircut. They sit amid a clutter of flat-screen TVs, watercoolers, bottles of Dash's Dusko whiskey, red Vampire Life vodka, and whiteboards with sketches of puffer vests.