Brewer, 49, will replace Brian Cornell on Feb. 1, 2012, at the start of the company's fiscal year, Walmart said. She most recently ran the retailer’s U.S. operations on the East Coast.

Walmart also promoted two other women, naming Gisel Ruiz to the role of Walmart U.S. chief operating officer and Karenann Terrell to chief information officer.

In her most recent role as president of the Walmart U.S. East business unit, Brewer was responsible for more than $100 billion in annual revenue, representing almost 1,600 stores and more than 500,000 employees.

Brewer joined Walmart in 2006 as a regional vice president after spending years at Kimberly-Clark Corporation. She was selected as one of the most powerful women in business by Fortune magazine in 2010 and 2011 and sits on the board of Lockheed Martin. She was the first chair of the Walmart President's Council of Global Women Leaders.

Sam's Club operates 610 stores; it had $49 billion in fiscal 2011 sales.