(CNN) -- Joan Smalls was 19 years old when she left her family's home in the countryside of northern Puerto Rico to pursue dreams of walking the runway.

In just four busy years, she has risen from department store catalog model to the ranks of fashion's most-sought-after models, walking for the likes of Jason Wu, Donna Karan and Tory Burch at New York's 2012 Fall Fashion Week.

Along the way, she has broken barriers by becoming the first Latina face of Estee Lauder's global marketing campaigns in 2011. She has done runway shows in New York, London, Milan, and Paris and graced the pages of British, French, Spanish and U.S. versions of Vogue several times over.

"Joan is a modern beauty with elegance, style and confidence," said Aerin Lauder, former senior vice president, and current style and image director, of Estee Lauder. "She is the perfect addition to Estee Lauder's global faces."

Not bad for someone who used to wear combat boots to casting calls so she could make the trek from Queens to Manhattan.

"I had to take a bus to then take the subway to then go in the city, so I wanted to be as comfortable as possible," she said. "I think that had a lot to do with it, and especially at the beginning, having to go to 10, 15 castings a day, you want to be as comfortable as possible."

She began wearing heels full-time when she switched agencies in 2009 and began working with IMG's Kyle Hager. Within a year, she landed her breakthrough gig in high fashion as the exclusive model for Ricardo Tischi's Givenchy 2010 Couture Show in January 2010.

"When you want something so bad and when something great happens, I think it's instinct that you say, this is gonna be the moment that's gonna change everything. Everybody is gonna see me a different way," she said. "I thank Kyle every day because he made such a big difference in my career and in my life."

She's come a long way before her 23rd birthday, and there's more on the horizon: She's the face of the spring/summer 2012 campaigns for Chanel, Lacoste and Calvin Klein Jeans, and work keeps coming in. Amid the glitz and glamour, she counts among her greatest achievements helping change perceptions of beauty in fashion and modeling.

"I just want to continue to break barriers and to show the industry and the world that beauty is diverse, and you don't have to be a certain stereotype to be beautiful," she said. "When you look at the world, the world isn't just one palette. It's a beautiful rainbow, and why not have someone to represent that rainbow?"