In a surprise move, Walmart has today announced its new CEO will be Doug McMillon, a 47-year-old who started out in the retail giant’s warehouse as a teen.

McMillon will take the helm of the world’s largest retailer effective February 1, when current president and CEO Mike Duke will step down.

Duke, 63, had been rumored to be considering retirement but an obvious successor had not been floated externally.

Walmart’s new CEO is the current head of Walmart International, overseeing the company’s growing interests in 26 countries outside the US.

McMillon has a long history with the store chain, having started out as summer employee in a distribution center in 1984 before heading to the University of Arkansas in Fayetteville, one town over from the retailer’s corporate headquarters.

In 1990, while pursuing his MBA, he rejoined the company in a Tulsa, Okla., Walmart store. He spent the intervening 23 years climbing the ranks, mostly in merchandising positions.

Billionaire Walmart chairman Rob Walton described McMillon’s ascension to CEO as a nod to the store chain’s “changing customer,” one that is increasingly international.

“A merchant at heart, Doug has both a long history with our company and a keen sense of where our customers globally are heading next,” said Walton in a statement.

“He has also shown strong leadership on environmental sustainability and a commitment to using Walmart’s size and scale to make a difference in the lives of people, wherever they might be.”

McMillon sits on the board of Walmart heiress Alice Walton’s Crystal Bridges Museum of American Art as well as the board of directors at Walmart Mexico.