"This is from Sam Walton," Mr. McMillon's new boss said, he recounted. "Have you fixed it?" At Walmart, a connection to "Mr. Sam" is currency. Mr. McMillon's main competitor for the job, industry experts said, was probably William S. Simon, the chief executive of Walmart U.S. Mr. Simon joined Walmart in 2006 from Brinker International, a company that owns restaurant franchises like Chili's Grill and Bar. "It looks like they took an insider over an outsider," said Sucharita Mulpuru, an analyst at Forrester. "Bill Simon joined more recently, he had more of a restaurant background," Ms. Mulpuru said. "Doug McMillon is more of a company lifer, so to speak. He's been at the company a long, long time." In recent years, Ms. Mulpuru said, the international arm of Walmart has been a greater engine of growth than either the domestic division or Sam's Club, and since 2009 Mr. McMillon has been running the international operation. In October, the company announced it would open up to 110 new facilities in China by 2016.