Under Armour's Kevin Plank famously started his athletic-apparel company when he was a University of Maryland football player in the '90s. (He was looking for a moisture-wicking, form-fitting undershirt to wear under his pads.) Today, Baltimore-based Under Armour pulls in $2.3 billion in annual revenue. It's the third-largest athletic brand in the world, behind Nike and Adidas, and Plank has his sights set firmly on becoming No. 1. His latest innovation, the SpeedForm Apollo running shoe, just might get him there. But creating it wasn't easy, as he explains to Inc. editor-at-large Tom Foster. 

First, Do One Thing Well

Focus is one of the most important things to have in your business. For the first five years, as we grew our company from zero to $5 million, we made, really, one shirt. Another way to say it is that a company needs to become famous for something, to find that niche. In those early years, we didn't try to keep up with the Joneses and make 10 other styles and different things; we created one thing. But that one thing was also generic enough--a white shirt with a black logo on the chest--that it could be a baseball shirt, a lacrosse shirt, a soccer shirt.

Stay True to Your Brand

I realized that it was not just this product I was building; it was a brand. Under Armour wasn't about the compression T-shirt; it was about the essence of it: performance. The shirt was a piece of equipment. It made you perform better. So now we make performance footwear and accessories as well.

When we first got into footwear in 2004, with a football cleat, we played it too safe. We said, Let's be respectful of the industry, learn it, not do something too crazy. But our customer was expecting us to be disruptive. It's not like we made bad product; it's just that the bar was higher than even we were aware of. We had to take a step back from the business and say, What is Under Armour? How do we incorporate what makes our apparel great into our shoes?

"I am challenging every one of our product teams to say they've created the next great product."Kevin Plank

Be Open to Wild Ideas

The idea for our new SpeedForm running shoe came from one of our manufacturers in China, one of the best bra makers in the world. He thought that the same kind of molding that creates comfort and support in athletic bras could work for shoes. So I put a team on his idea to see if we could design something new. It forced us to completely deconstruct the product and the process. We realized, if there's one thing that anchors a running shoe, it's the heel cup. Like a bra cup, what we came up with is molded and doesn't have a stitch in it. The way we applied the mid- and outsole was different as well. The shoe is lightweight but supportive. It's a whole new way of making footwear.

Never Stop Inventing

There's a simple mantra that hangs above every one of our product teams. It says, "We have not yet invented our defining product for the brand." The foundation of the company is our compression shirt, but I am challenging every one of our product teams to say they've created the next great product. That was the challenge we gave the members of our footwear team. They came back and said, "We think we have the coolest running shoe ever built." We haven't declared it a victory yet, but this may become one of the pillars of Under Armour.

Previously in Inc.: Kevin Plank was on the cover in December 2003 (How I Did It). His company also made the Inc. 500 list of fastest-growing private companies that year.