Abel and Ajit Jain are being added as directors.
To fit Abel and Jain in, Berkshire's board also voted to raise the number of directors to 14 from 12. Continuing as a vice chairman is Charles Munger.
Mr Buffett has led Berkshire Hathaway for more than four decades, turning it into a complex conglomerate with holdings in freight rail, major insurance companies, real estate, newspapers and utilities.
The hard-driving Buffett, who has been reluctant to name a successor, said in the past that Berkshire's board knows who would take over if something were to happen to him.
He declined to say how long he expected to remain at the helm but said: "Ten years would be a long time". He said jokingly, "I wasn't much to start with".
None of the executives was immediately available for interviews.
But on the stock market today, Berkshire's "B" shares traded 0.1% lower on the news, near 203. He joined the company in 1992. His Iowa-based unit now runs several power companies in the United States, Canada and Britain, as well as natural gas pipelines and solar and wind farms. Ajit Jain, 66, will be vice chair of insurance operations. He joined Berkshire's insurance group in 1986.
Buffett said he would not take a short position on bitcoin futures.
Mr Buffett told CNBC that the changes should be nearly imperceptible from the outside. Munger put forth the idea for Abel, Jain and himself to all have vice-chair titles, Buffett said.
Todd Combs and Ted Weschler, who are Buffett's investment deputies, are expected eventually to succeed Buffett as Berkshire's chief investment officer. He now serves as executive vice president of National Indemnity Co.