The second-longest-serving member of the House -- Rep. John Conyers, D-Mich. -- served on Dingell's staff before being elected to Congress in his own right.
If he continues getting re-elected, Dingell could become the longest-serving member of Congress -- including service in both the House and the Senate -- in January 2013.
The late Sen. Carl Hayden, D-Ariz., holds the record for combined service in Congress at nearly 57 years, and Sen. Robert Byrd, D-W.Va., has the longest tenure of any current member of Congress, with a combined 56 years in the House and Senate.
Dingell has had a leading role in some of the biggest congressional achievements over the past few decades, including the Clean Air Act, children's health insurance and cable regulations. But he hasn't achieved longevity by being everyone's friend. His sometimes imperious manner and tough bargaining tactics have rankled colleagues who have struggled to understand a powerful chairman's intentions.
He has frustrated Democratic and Republican House speakers alike -- including Pelosi, who has in the past supported Democratic challengers in Dingell's House races. Pelosi also offered quiet encouragement to a successful attempt to wrest his committee gavel from him last year.
Dingell has clashed frequently with the left in his party in recent years, most famously over his passionate defense of the automobile industry in his native Michigan. His wife since 1981, Debbie Dingell, is a longtime executive with General Motors.
Dingell's support for Detroit has led him to oppose tighter emissions standards for cars and trucks -- a position that emboldened Rep. Henry Waxman, D-Calif., to launch his surprise bid to oust Dingell as chairman of the powerful House Energy and Commerce Committee after the November election.
Waxman's bid succeeded, in a secret ballot vote of the House Democratic caucus that shocked many observers of Congress. Dingell wound up accepting a new role as "chairman emeritus" of the committee -- notwithstanding the rebuke delivered by his colleagues.
"This was clearly a change year, and I congratulate my colleague Henry Waxman on his success today," Dingell said in accepting the vote's outcome.
The deal he worked out with Waxman and House leaders gives Dingell an expanded role on health care. He has filed his national health insurance bill -- every year, it gets the label H.R. 15, numbered to match his congressional district -- in Congress going back to 1943.
"He feels like he has a commitment to people of his district not to go away," said Steve Elmendorf, a veteran Democratic operative in Michigan and national politics. "It helps to have people around who know the institutional history, who know how things are done."
Dingell said he feels a special responsibility to work on health care and to address the financial crisis, given the fact that he's one of the few remaining members of Congress with firsthand memories of the Great Depression.
"History never repeats, but there's a lot you can learn from history if you watch it," he said. "I won't say this is a repetition of the Depression, but I've got to be honest with you, there are some very scary parallels. I hope that we learn the lessons that the Depression taught."