When Tracy Britt arrived in Omaha, Neb., in 2009 to meet with Warren Buffett, she brought a Harvard M.B.A., a glittering resume and a boatload of ambition. But she also brought the famed investor a gift to highlight their shared Midwestern roots: a bushel of corn and a batch of tomatoes.
The seed Ms. Britt planted that day yielded quick results: a job for Ms. Britt as Mr. Buffett's financial assistant at Berkshire Hathaway Inc. Almost four years later, it has blossomed further, with Ms. Britt emerging as one of Mr. Buffett's top lieutenants and even serving as chairman of four companies within his $284 billion conglomerate.
Ms. Britt, now 28 years old and more than five decades younger than her boss, occupies a role unlike any other within Berkshire. With an office next to Mr. Buffett's at Berkshire's headquarters, Ms. Britt helps with financial research, accompanies Mr. Buffett to meetings and occasionally drives him around town. The billionaire gradually tacked on additional responsibilities.
The firms in which she serves as chairman, including building-products company Johns Manville Corp. and paint manufacturer Benjamin Moore & Co., total more than $4 billion in annual sales. In March, a few weeks after Berkshire and Brazilian investment firm 3G Capital said they would buy ketchup maker H.J. Heinz & Co. for $23 billion, Mr. Buffett sent Ms. Britt to Brazil, according to people familiar with the matter.