DETROIT (AP) -- The leader of the new General Motors was done in by an old problem at the nation's largest car maker: Change wasn't happening fast enough.
GM's board and CEO Fritz Henderson parted ways Tuesday, the board upset that the automaker's turnaround wasn't moving more swiftly and Henderson frustrated with second-guessing, two people close to the former CEO said.
Board Chairman Ed Whitacre Jr., the former head of AT&T Inc., will take over as CEO while a global search is conducted.
It was unclear whether Henderson or the board moved first in the surprise resignation, which came just hours before Henderson was to be the high-profile keynote speaker at the Los Angeles Auto Show. At a hastily called news conference at General Motors Co.'s downtown Detroit headquarters, Whitacre would not answer questions, but said the board and Henderson agreed that he should step down.
Whitacre thanked Henderson, 51, a lifelong GM employee, for his leadership and said the company is on the right path toward offering high-quality cars and trucks worldwide.
"We now need to accelerate our progress toward that goal," the 68-year-old Whitacre said in a brief appearance.
Both men were chosen for their jobs by the U.S. government, which owns more than 60 percent of the Detroit automaker in exchange for giving it billions in loans. But Henderson is a GM insider, while Whitacre had no car experience before taking the GM chairmanship.
"I don't think this has much to do with Fritz Henderson's performance, I think it's just the wrong time to be a GM lifer," said Logan Robinson, a former Chrysler attorney and professor of corporate governance at University of Detroit Mercy.
Industry analysts said GM likely would look for someone like Ford Motor Co. CEO Alan Mulally, who was hired in 2006 from aerospace giant Boeing Co. Mulally also had no automotive experience, but unlike Whitacre, was well-versed in manufacturing.
An Obama administration official said Tuesday in a statement that "this decision was made by the board of directors alone. The administration was not involved in the decision."
Henderson, who rose through GM's ranks over a 25-year career, took over in March after the government forced out former CEO Rick Wagoner. A few months later, GM entered bankruptcy protection and Henderson led the company through a painful government-led and court-supervised reorganization. The company emerged from court protection in just 40 days cleansed of massive debt and burdensome contracts that would have sunk it without roughly $52 billion in federal loans.
The people close to Henderson, who asked not to be identified because Henderson has not spoken, said he was frustrated from the beginning by the board and government push for faster change and other questions about his decisions.
Henderson, one of the people said, was confident that the company was making progress and thought he deserved more autonomy. In the past few months GM has stabilized its U.S. market share at around 20 percent and has shown some monthly sales increases in the U.S. and Asia.
Henderson also has been largely successful in his goal to scale down GM to just four core brands: Chevrolet, Cadillac, Buick and GMC. He won a tentative sale of Hummer to a Chinese construction machinery maker. But attempts to sell the company's other brands have hit obstacles.
Swedish luxury sports car maker Koenigsegg Group AB backed out of a deal to buy GM's Saab brand. GM said Tuesday it has some interested bidders but will wind down Saab if nothing materializes by the end of the year. Henderson's bid to sell Saturn to race car mogul Roger Penske fell through and the brand is now liquidating.
And on Tuesday, GM released November sales figures that were 2 percent below the same month last year, when sales hit a 26-year low. The decline came after Whitacre began pushing for increased sales and market share.
Whitacre and the board have become increasingly active in the company's decisions, at times challenging some of Henderson's moves. In November, the board voted to abandon plans to sell GM's European Opel unit, reversing an earlier option favored by Henderson to sell it to a group led by Canadian auto parts supplier Magna International Inc.
"I think there was a perception he was too much of an insider," said Ken Elias, partner with Maryann Keller and Associates, an auto industry consulting firm. "The bankruptcy was not something that occurred because of the recession last August, it was coming for decades. The reality is GM truly needs an outsider as a leader that has no attachment."
Whitacre, a Texan, is known as a blunt talker. He was also the highest-paid telecommunications executive in the country when the retired in 2007, and his compensation was starting to draw criticism from shareholders and activists.
He joined Southwestern Bell, part of the national AT&T monopoly, in 1963 as a facility engineer. When he took over as CEO in 1990, the company was the smallest of the seven "Baby Bells" spun off in the 1984 government-ordered breakup of the Bell system.
Under Whitacre, the company started snapping up other parts of the old AT&T. It acquired three of its larger Bell siblings, as well as the long-distance company that bore the AT&T name.
His crowning achievement was the 2006 acquisition of BellSouth, which gave AT&T full ownership of Cingular Wireless and a leading role in the growing cellular industry.
GM could face difficulty in recruiting Henderson's replacement. Like other struggling companies that have received federal bailout money, any compensation package would have to be approved by federal pay czar Kenneth Feinberg.
In an agreement reached in October with Feinberg, Henderson's pay was cut 25 percent to $950,000, about half of what he made in 2008. In addition, Henderson received shares worth $4.2 million, to be exercised when GM becomes a public company again, perhaps late next year.
AP Auto Writers Dee-Ann Durbin in Detroit and Dan Strumpf in New York, and AP Technology Writer Peter Svensson in New York contributed to this report. Ken Thomas reported from Washington.