The move has been seen as all but certain since Whitacre, 68, announced on December 1 that he would take over as acting CEO after predecessor Fritz Henderson was ousted after eight months.
The person who confirmed the permanent appointment of Whitacre, who is also GM's chairman, requested anonymity ahead of the formal announcement later on Monday.
Whitacre, the former chief executive at AT&T , became GM chairman last July at the request of the Obama administration as the company emerged from a government-sponsored bankruptcy that included more than $50 billion in financing.
Whitacre has said Chris Liddell, who joined GM as chief financial officer from Microsoft Corp , is a leading candidate to succeed him.
In December, Whitacre announced a shake-up of the automaker's senior leadership, tightening his hold on GM's reins and installing a new group of executives to head the automaker's troubled U.S. operations.
GM has lost $88 billion since 2005. Whitacre has said the automaker could post a profit this year as it aims to relist its shares as soon as late 2010.
The company had hired Spencer Stuart to look for a permanent CEO, but the executive search firm never presented a list of candidates to the board, people familiar with the matter have said.
Whitacre, who will host a press conference at 11:30 a.m. EST (1630 GMT), becomes the third CEO at the largest U.S. automaker in 10 months.
Henderson, 51, was a career GM executive who had risen through company ranks and steered the automaker through its 40-day bankruptcy.
Rick Wagoner, 56, was CEO from 2000 until last March, when the Obama administration's autos task force ousted him.
Henderson and Wagoner each tried to remake GM into a leaner and faster-moving company, but both were seen as acting too slowly and without the credibility of an outsider.
The three U.S. automakers -- GM, Ford Motor Co , and Chrysler Group LLC -- now have chief executives who made their careers outside Detroit.
Alan Mulally, who became Ford's CEO in 2006 after leaving Boeing , has reshaped the No. 2 U.S. automaker and steered it clear of a federal bailout.
Chrysler is led by Sergio Marchionne, also the chairman of Fiat SpA , which took management control as part of the automaker's government-brokered bankruptcy.
(Additional reporting by Soyoung Kim and David Bailey; Editing by Dave Zimmerman and Lisa Von Ahn)