In January, Campbell was promoted from her role as head of the southern division of the home-improvement retailer to run all of Home Depot’s U.S. stores. That makes her responsible for some 90% of the company’s $88.5 billion in 2015 revenues and 350,000 employees—and a direct report to CEO Craig Menear. The Jamaican-born Campbell, known for connecting with associates, is part of a team that is firing on all cylinders: Sales and earnings both rose dramatically, helped in part by the recovering U.S. housing market.