Waxman is an avid environmentalist and booster of health care programs - and a home-state ally of House Speaker Nancy Pelosi. He defeated Dingell on a 137-122 vote in the Democratic Party caucus, capping a bruising intraparty fight.
The Energy and Commerce panel is one of the most important House committees, with sweeping jurisdiction over energy, the environment, consumer protection, telecommunications and health care programs such as Medicaid and the popular State Children's Health Insurance Program.
Dingell has been the top Democrat on the panel for 28 years and is an old-school supporter of Detroit's carmakers and other big industries such as electric utilities. His bitter battles with Waxman over clean air issues date to the Reagan administration and were recently revived as Waxman complained that the committee has been too slow to address global warming.
Dingell comes from an era of autocratic committee chairmen and has had to adapt to a House in which power is consolidated around Pelosi, who has clashed with him in the past. Last year, in a move that undercut Dingell's power on the global warming issue, she created a special panel led by Massachusetts Rep. Edward Markey to make the case for bigger reductions in greenhouse gases. Pelosi did not publicly take sides in the new vote, but her support of Waxman was well known and played a role in the strong tally.
Waxman was the candidate of change in a year dominated by that theme. He likened the first years of the Obama administration to a once-in-a-generation opportunity to get things done in Washington.
"The argument we made was that we needed a change for the committee to have the leadership that will work with this administration and members in both the House and the Senate in order to get important issues passed in health care, environmental protection, in energy policy," Waxman said after the vote.
Waxman, 69, has a lengthy congressional resume of aggressive investigations and legislative action.
Dingell's reputation for putting Detroit's auto interests above all else didn't help his campaign to keep his job - especially as automakers seeking a bailout have been taking a public relations pounding on Capitol Hill.
His defenders said he had done nothing to deserve being dumped, pointing to a long list of accomplishments and the panel's busy workload over the past two years, including successfully enacting an energy bill that would raise automobile fuel economy standards to 35 miles per gallon by 2020.
Driving Waxman's bid was the issue of global warming, a top issue for Obama. Waxman is expected to move legislation with tougher emissions standards than Dingell would have.
Environmentalists say Dingell has acted too slowly on global warming. A bill he released last month was a poke in the eye to Waxman and Pelosi, D-Calif., since it would prevent states, including California, from setting tougher auto emissions standards than the federal government.
"Waxman's victory is a breath of fresh air - of clean air. It was a stunning defeat for the corporate lobbyists on K Street," said Frank O'Donnell, president of Clean Air Watch. "It shows that a majority of the House Democrats are ready to work with the incoming Obama administration on effective global warming legislation."
Still, taking on global warming will be anything but a cakewalk.
A controversial "cap and trade" mechanism in which permits are sold is tantamount to a huge tax on carbon dioxide emissions and will face resistance from coal state Democrats and moderate party members - to say nothing of Republicans.
"This decision sends a troubling signal from a majority that has promised to govern from the center," said House GOP leader John Boehner of Ohio. "They moved away from Chairman Dingell because he is committed to approaching energy and environmental issues in a manner that protects American jobs."
Bill Kovacs, a vice president at the U.S. Chamber of Commerce, said Dingell brought a balanced and methodical approach to environmental policy and sought the input of the regulated industries.
It's the difference of "one trying to keep everyone in the system and one knowing exactly where they want to go and how they are going to get there," Kovacs said.
