In the weeks leading up to April’s Masters golf tournament, defending champion Jordan Spieth’s smiling face was seemingly everywhere. He hit drives with Stephen Colbert on the Late Show, yakked it up with Charlie Rose, stared out from the cover of Golf magazine, and was the subject of a rare double-episode of Golf Channel’s popular interview show, Feherty.

During all these appearances, the clean-cut phenom sported just one brand of clothing: Under Armour (UA). Save for a few segments when the interlocking UA was hidden under the green jacket he won at Augusta National last year, the logo was plainly visible on every hat, shirt, and pullover he wore.

Just 17 months ago, Spieth was a relatively unknown 21-year-old with only a few professional wins under his belt when Under Armour made what outwardly looked like a curious decision. It ripped up his original endorsement contract, and signed him to a brand new 10-year deal.

“He had already shown me that he was going to be around a while at that elite level, so we wanted to make sure that we were paying him as such,” says Ryan Kuehl, Under Armour’s vice president of sports marketing and sponsorships, who first targeted Spieth when the Texan was just a teenager. “Did I know he would be this good this fast? Obviously not. But I knew we could build a business around him. We structured the deal for a top-five player. He’s performed every bit of that if not more.”

Let’s go with “more.” Just three months after inking the new deal, Spieth burst onto the world scene by tying the Masters record for the lowest score. The TV exposure he earned for Under Armour during the four-day broadcast was worth $33.6 million to the company, sports sponsorship analytics expert Eric Smallwood told USA Today. Clad in Under Armour gear, Spieth graced the cover of Sports Illustrated, and went on to win the U.S. Open and break Tiger Woods’s record with $22 million in on-course earnings for the season.

In the process, Spieth sold a whole lot of shirts for Under Armour. When the company released its 2015 earnings, it attributed much of the 22 percent increase in apparel net revenues to growth in the golf sector. Overall, revenue increased 28 percent to $3.96 billion.

Under Armour prides itself on zigging when its competitors zag.

Spieth’s emergence was a major coup for Under Armour, which has had quite a few of them in recent years. In 2013 the company signed basketball player Stephen Curry, who had been with rival Nike, just as he was primed to evolve from a player with potential to the biggest star in the NBA. Last year he won the MVP award and a championship with the Golden State Warriors, and this season he has become the face of the league.

Cam Newton was the NFL’s MVP and led his Carolina Panthers to the Super Bowl. Tom Brady transformed from the 199th pick in the 2000 NFL draft to a global icon. Like Spieth, these athletes—also Under Armour endorsers—are brash, supremely talented, and, at some point in their careers, felt they were overlooked and underrated—exactly the way Under Armour sees itself. When it comes to picking the players who burnish its brand, tell its story, and most importantly, sell its products, Under Armour has been, like the athletes it signs so frequently, in the zone.

One of Under Armour’s stars has never won a championship ring or any most valuable player award. And she never will.

In 2012, the company launched a campaign to “re-define the athlete and allow women to talk about beauty through the lens of sport,” says Adrienne Lofton, UA’s senior vice president of global brand marketing. It needed someone who would transcend the world of traditional sports to serve as the face of its women’s brand.

“We always talk about the athletes that have the DNA that best aligns with our brand,” Lofton says. “We call it underdog spirit. It’s this ability to constantly feel like there’s this chip on your shoulder, this need to keep pushing and driving.”

That describes ballerina Misty Copeland to a tee. Copeland didn’t start dancing until she was 13 and repeatedly was told that her body type wasn’t suited to the discipline. But she eventually became the first African-American principal dancer in the American Ballet Theatre (which, yes, happened after Under Armour brought her onboard).

“As we talked to women around the world, it’s not so much competitive sport that inspires them, it’s everyday women and in ‘nontraditional’ sports like dance,” Lofton says. “After meeting Misty and hearing her story and hearing her passion to tell the next generation of young girls they can be her in 10 years, we wanted her to be our microphone.”

Under Armour prides itself on zigging when its competitors zag, so pitching the idea of signing a ballerina to CEO Kevin Plank, who has final say on most endorsement deals, wasn’t difficult. Kuehl helped close the deal with Copeland’s agent, Gilda Squire, after a meeting at Norma’s in Le Parker Méridien Hotel on West 56th Street in Manhattan. In 2014, Copeland was officially added to Under Armour’s roster, but one question remained: What would the company do with her?

Copeland obviously can’t wear Under Armour products when she performs, so they set about creating a narrative around her story. As part of the “I Will What I Want” campaign, an ad featured her (and her otherworldly calves) dancing in an Under Armour outfit while a young girl reads a rejection letter from a ballet company. The ad went viral, and now has more than 10 million views on YouTube. The Under Armour deal has been mutually beneficial, helping propel Copeland’s popularity beyond the world of ballet. UA’s brand awareness among women is the highest it has ever been.

“The biggest shift since signing was the respect I started to receive from men,” Copeland says.

“The biggest shift since signing was the respect I started to receive from men,” Copeland says from Detroit, where she is performing. “They really began to see me and dancers in general as athletes. Overall, the campaigns have definitely broadened my visibility and really put ballerinas on the map, giving us the long due respect from the American public we deserve.”

The success of the Copeland deal is one reason why Plank thinks women’s apparel sales can one day surpass men’s for the company. It may sound hyperbolic, but that’s the kind of thinking that’s enabled him to build Under Armour from his grandmother’s basement into the second-largest sports apparel company in the U.S.

“Under Armour made a huge investment in Misty and it was a huge risk,” Squire says. “I don’t think another athletic company would have [done it]. If that was the case, we would have been getting calls from all kinds of athletic wear brands. But we weren’t.”

Companies like Nike, Adidas, and Under Armour sign athletes to endorse their products for two major reasons, says Haiyang Yang, assistant professor of marketing at Johns Hopkins Carey Business School. They want to appeal to the customer’s rational side—if Steph Curry is wearing those shoes and because he’s the best, his shoes must be the best too—and to their emotional side—I love Steph Curry and want to feel close to him by wearing his shoes.

“You are picking somebody who is congruent with the brand image you are trying to portray,” Yang says. “If the brand image is, ‘We are the underdog, but we are striving to become the best,’ it might actually be better to align your brand with a rising star than somebody who has already achieved everything. There are probably a lot of people who have the potential to become a superstar, but how do you know which one will? It’s a probability game. I’d say Under Armour did their homework very well. They made some bets, and their bets paid off.”

A former long snapper in the NFL, Ryan Kuehl is built like a grizzly, but has the disposition of a teddy bear. His affable manner and experience dealing with athletes has helped him land some of Under Armour’s most important endorsers, including Tom Brady in 2010.

“Tom brought a different level of eyeballs, and quite frankly, scrutiny,” he says. “Tom has allowed us to sign a lot more athletes. It’s sort of like that Good Housekeeping seal of approval. Anytime we have a chance to put our products on our athletes, it authenticates us in the sense that people feel like we’re going in the right direction. They’re all our small North Stars.”

There are three traits Kuehl values most in Under Armour’s potential “partners,” as the company calls its endorsers: character, talent, and style. “In that order,” he says. His marketing team works with the business units to establish goals, and then finds athletes who fit the protocol.

Plus, Under Armour gets in early. The company was already designing shoes for Curry in 2009, the year he was drafted, even though he was years away from being on Under Armour’s roster. According to ESPN, it was that forward thinking—plus a botched Nike re-signing meeting and some convincing from former Warriors teammate and Under Armour partner Kent Bazemore—that led Curry to sign in 2013.

Similarly, Kuehl was watching Spieth during a practice round back at the 2012 AT&T National at Congressional Country Club in Bethesda when he knew he’d found his man. Kuehl walked with Spieth’s group for the front nine, observing from afar how the then-18-year-old interacted with fans, his fellow players, and his caddy. On the back nine, Kuehl introduced himself.

“The thing that stuck out to me was how strong Jordan was mentally and how much he cared about winning,” Kuehl says. “In golf, you can have a really good life by finishing 25th every tournament. You’re going to make a ton of money; you’re going to drive fancy cars. But to win takes something different. From Jordan’s perspective that came through from the first time I met him. I think that’s special in the sport of golf—what he’s willing to do to compete and win.”

“When I went up to Baltimore, it was a no-brainer,” Spieth said.

When Spieth turned pro later that year, he hired Jay Danzi to be his agent. Danzi had represented golfer Hunter Mahan when Mahan became Under Armour’s first golf partner in 2004. Quickly, Kuehl arranged for Danzi and Spieth to visit the company’s Tide Point campus. They met with various Under Armour product and business teams and ate lunch with Plank.

“I went up there, and when I left Baltimore it was a no-brainer,” Spieth told USA Today. “I was going with them. The whole atmosphere there, seeing the headquarters, I loved the attitude there.”

The deal the parties reached was unique in the golf world. Under Armour bought all the spots on Spieth’s apparel, meaning its logos would be the only ones visible on his attire.

“Jordan likes having the clean look that Under Armour provided him—not looking like a NASCAR driver with a bunch of different logos on him,” Danzi says. “It’s clean and athletic but still being classic. It fit well from day one.”

Spieth was named PGA Tour Rookie of the Year in 2013, and finished second in the Masters in 2014. Soon after, Under Armour decided to lock him up for the foreseeable future, signing him through 2025. Although terms were not released, Golf Digest reported that “the deal, which industry insiders say has ‘Tiger-like numbers,’ includes an eight-figure guarantee annually, bonus benchmarks (for things like winning a major), stock options and, in the future, a signature line of clothing.”

At this year’s Masters, Spieth seemed poised to win again. Wearing a blue-striped Under Armour shirt and a white UA hat, he took a five-shot lead to the back nine, where America watched in agony as he unraveled, ultimately finishing tied for second.

After the round, he was widely praised for the class he exhibited while facing the cameras, the UA logo visible in each painful shot. Golf can be a fickle and cruel game, and as anyone who’s played it at any level can tell you, failures far outnumber successes.

When the shell-shocked Spieth talked to the press after the heartbreak, he referred to himself and his team with words that could practically be an Under Armour slogan: “There is no give-up in us.”