The person was not authorized to speak publicly ahead of Dingell's announcement.
The 87-year-old Michigan Democrat has served in the U.S. House since winning his late father's seat in 1955. He became the longest serving member of Congress in history on June 7 when he eclipsed the record held by the late Sen. Robert Byrd of West Virginia.
His plans were first reported Monday morning by The Detroit News and the Detroit Free Press.
"I'm not going to be carried out feet first," Dingell told The News. "I don't want people to say I stayed too long."
Dingell is the former chairman of the powerful House Energy and Commerce Committee and the Democrat has been a master of legislative deal-making and staunch advocate for the U.S. auto industry.
Dingell has played a role in a number of major pieces of legislation, including President Barack Obama's health care overhaul and Medicare.
Dubbed "Big John" for his imposing 6-foot-3 frame and sometimes intimidating manner, a reputation bolstered by the wild game heads decorating his Washington office, Dingell has served with every president since Dwight D. Eisenhower. He also was known as a dogged pursuer of government waste and fraud, helping take down two top presidential aides while chairman of a powerful investigative panel.
"Presidents come and presidents go," former President Bill Clinton said in 2005, when Dingell celebrated 50 years in Congress. "John Dingell goes on forever."
Dingell had a front-row seat for the passage of landmark legislation including Medicare, the Endangered Species Act and the Clean Water Act, all of which he supported.
He also was accused of stalling the Clean Air Act to help auto interests. His hometown, the Detroit suburb of Dearborn, was home to a Ford Motor Co. factory that was once the largest in the world.
One of his proudest moments came in 2010, when he sat next to Obama as the $938 billion health care overhaul was signed into law. Taking up his father's cause, Dingell had introduced a universal health care coverage bill in each of his terms.
For 14 years he chaired the powerful House Energy and Commerce Committee, which oversees industries from banking and energy to health care and the environment. He also led its investigative arm, which produced several high-profile cases.
He often has used his dry wit to amuse his friends and sting opponents. Even when he was in a hospital in 2003 following an operation to open a blocked artery, he maintained his humor.
"I'm happy to inform the Republican leadership that I fully intend to be present to vote against their harmful and shameless tax giveaway package," he said from the hospital.
His critics called him overpowering and intimidating. And the head of a 500-pound wild boar looking at visitors to his Washington office only boosted that reputation, as did the story behind it: Dingell is said to have felled the animal with a pistol as it charged him during a hunting trip in Soviet Georgia.
Yet the avid hunter and sportsman, whose office was decorated with big game trophies, was hard to typecast. He also loved classical music and ballet — his first date with his wife, Debbie, a prominent Democratic activist whom he affectionately introduced as "the lovely Deborah," was a performance of the American Ballet Theater.
Born in Colorado Springs, Colo., on July 8, 1926, John David Dingell Jr. grew up in Michigan, where his father was elected to Congress as a "New Deal" Democrat in 1932. After a brief stint in the Army near the end of World War II, the younger Dingell earned his bachelor's and law degrees from Georgetown University.
Following the sudden death of his father in September 1955, Dingell, then a 29-year-old attorney, won a special election to succeed him.
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