Under Armor's Founder, Kevin Plank

It's a warm evening in May, the night before the Preakness Stakes, and hundreds of people are packed into a vast white party tent at a horse farm 17 miles northwest of Baltimore. Some are getting drunk at the tent's multiple whiskey bars. Others stand on a veranda that overlooks the green hills of this part of Maryland, holding plates of barbecue and wiping brisket sauce from their lips.

Kevin Plank does this every year – throws this party, invites everyone he knows. Tomorrow he'll take a bunch of these people to the race, try to hook them on horses, show them another side of a city they thought they knew from the corruption and drug-dealing on 'The Wire,' but tonight he's just trying to make sure everyone's having a good time. Plank, age 41, with alert, shining eyes and the bland good looks of a dad in a mail-order catalog, is the founder and CEO of Under Armour, the $2 billion athletic apparel and footwear company that employs 1,300 in an old Procter & Gamble detergent factory on the Baltimore waterfront. He greets a string of Baltimore politicians, NBC News contributor Harry Smith, former NFL linebacker LaVar Arrington, and former gymnastics coach Bela Karolyi, who's decked out in a cowboy hat. He greets his buddies from his Catholic high school and the University of Maryland, where he walked onto the football team. ("I'll go over to my college friends," Plank tells me later. "They're like, 'Come on, come on, let's do a shot.' I can't do a shot; the governor's over there.") After a time, he ducks into the manor house, which he's decorated with framed pictures of the famous horses that used to train here, including Native Dancer, who won the Belmont Stakes and the Preakness Stakes in 1953 and damn near won the Kentucky Derby, as well.

Plank bought the farm in 2007, partly out of irritation. He kept hearing that the Preakness, which has been held in Baltimore since 1873, might be moving out of Maryland. Yet nobody in Baltimore seemed to care. This baffled him. He thought, What are Baltimore's great brands? The Orioles. The Ravens. Crab cakes. Johns Hopkins. And the Preakness. "People are, like, 'Horse racing's going away,'" says Plank. "It's a 134-year-old tradition, and you're ready to let it walk?" So he snapped up Sagamore Farm, the 530-acre ranch that for generations had been owned by the Vanderbilt family, who'd let it go to seed. Plank hired one of his high school pals, Tom Mullikin, to restore the farm to its former glory and breed horses that could one day contend for the Preakness, even the Triple Crown. Sagamore now employs 26 people full-time. One of Plank's horses, Tiger Walk, finished eighth in the 2012 Preakness. "I like fixing broken things," Plank says.

In the tent, I meet a former steeplechase jockey named Sean Clancy. "He's different from the typical young, self-made man who's tried to bull his way to the top," Clancy says of Plank. "A lot of guys would just go to a sale, or buy million-dollar horses that have already proven themselves on the racetrack, and not go to the lengths that Kevin went to, buying that farm, sinking money into it, restoring it. He still has kind of an old soul about it."

Out on the hillside, two hot-air balloons go up and down on tethers, giving rides to the guests. A fire pit crackles, and the humid night fills with happy, drunken chatter, the hills blurring in the dusk. The air smells of beef and perfume. "I love seeing people," Plank tells me later. "I love blowin' their minds. I love that Gatsby-type party." But the party isn't excess for the sake of excess. It has a purpose: to keep a horse race in Baltimore – to do his share in saving the Preakness – while continuing to grow the company that has given Kevin Plank the resources to fix broken things.