ARLINGTON, Va. — It was her last time as an election night anchor, but Judy Woodruff was not in the mood to talk about how she was feeling. With Congress hanging in the balance and election denialism in the air, she was too busy, too focused on the task at hand, to reflect on how she had gotten to this moment in a career that began more than 50 years ago.

“Maybe when the evening is over and we wrap it up and give each other a high-five or a hug or whatever we do, maybe then it will hit me,” she said at 7:46 p.m. on Tuesday, during a rare break in an eventful broadcast that would stretch past midnight.

One of the leading television journalists of her generation, Ms. Woodruff, 75, made her name while chronicling Jimmy Carter’s presidential campaign for NBC in the mid-1970s, a time when it was exceedingly rare for women to cover politics. On Tuesday, while waiting for the midterm results to come in, she was sitting with her usual ramrod-straight posture on the set of “PBS NewsHour,” the no-nonsense nightly news program that she has led as the sole anchor and managing editor since 2016.

A takeout dinner was within reach — corn and crab chowder in a white to-go container, with a whole wheat roll on the side — but she wasn’t able to have more than a few spoonfuls before she had to go back on the air.

“I have been so consumed in the last few days with poring over newspapers and research papers,” she said. “I am trying so hard not to make a mistake, to get somebody’s name wrong, to call somebody a Democrat who is a Republican, to pronounce somebody’s name wrong.”

Ms. Woodruff, who is known for an evenhanded, down-the-middle style, announced in May that she would leave her job at the end of the year. Her last night as the anchor of “PBS NewsHour” will be Dec. 30. She plans to stay on at the public television network in the role of senior correspondent at least through the 2024 elections, and she will also host a new segment for PBS NewsHour, “Judy Woodruff Presents: America at a Crossroads.”

“When I made the decision to stop anchoring, I asked myself, ‘What are the most important questions that journalists should be answering?’” Ms. Woodruff said. “It was right there in my face: How did we end up so divided, so at each other’s throats, families divided, work colleagues divided, neighborhoods divided?”

She is that rare thing — a longtime Washington insider untouched by controversy. “I don’t know anyone who would have a bad thing to say about her, which is unbelievable for someone who has been a television star for all these years,” said the longtime Washington journalist Sally Quinn, who was known for hosting dinner parties for the power set.

“You’re not going to find dirt or edge,” Ms. Quinn continued. “I would tell you, maybe tell you quietly, but there is nothing there. There is no balance to a story about Judy Woodruff.”

During interviews for this article at her home in Washington, D.C., and the WETA-TV studio in Arlington, Va., where “PBS NewsHour” is produced, it seemed as if the last thing Ms. Woodruff wanted to talk about was her legacy.

“Judy would never make herself the story,” said the “60 Minutes” correspondent Lesley Stahl, who has known Ms. Woodruff since they were both White House correspondents during the Carter and Reagan administrations. “It’s a cliché, but in the case of Judy Woodruff, it couldn’t be more true.”

When Ms. Woodruff got her start, there were only three major broadcast networks and millions of Americans were content to get their news once a day from the plain-spoken CBS News anchor Walter Cronkite. The noise and partisanship that would come to characterize political coverage with the advent of cable TV and digital media were still a long way off.

Ms. Woodruff has never veered from the old style. After she poses a question, she listens to the answer. Politeness is her brand. It’s an approach that has earned her the respect of politicians on both sides of the aisle.

“Everyone I know feels comfortable having an interview with Judy, because you know that the questions will be fair and you’ll have an opportunity to get your points across,” said Marc Short, the onetime chief of staff to former Vice President Mike Pence and an occasional “PBS NewsHour” commentator.

“She is so respected, objective, and she gives you a chance to speak, which is a good thing,” House Speaker Nancy Pelosi said on Tuesday at the WETA-TV studio, moments after she had given Ms. Woodruff one of her first interviews since the attack on her husband. “She has her knowledge, so you feel as if you’re talking to someone who really understands democracy, legislation and the rest. And that’s not universally applicable.”

Jeffrey Goldberg, the editor in chief of The Atlantic, said that Ms. Woodruff’s emphasis on civility has made her stand out. “Judy might be the last grown-up in Washington journalism,” he said. “She has been a model of restraint, coolness and appropriate professional distance from the news, and that reinforces her credibility.”

A downside of her measured approach is that it risks making her look old-fashioned. In the opening moments of the Oct. 22 episode of “Saturday Night Live,” Heidi Gardner, a cast member, faced the camera with her hair coifed into a perfect Woodruffian bob: “Good evening, I’m Judy Woodruff and this is the ‘PBS NewsHour.’ We’re what your grandma is talking about when she says, ‘I saw this on the news.’”

She grew up the daughter of William H. Woodruff, a chief warrant officer in the U.S. Army, and Anna Lee Woodruff, who didn’t work outside the home. Judy’s army-brat upbringing meant she had lived in Taiwan, Germany and five American cities by the time she was a teenager.

The family settled in Augusta, Ga., after her father retired from the military and took jobs as an appliance salesman and a security guard. In the summers of 1966 and 1967, Ms. Woodruff worked in the Washington office of Robert Stephens Jr., a Democratic Congressional representative from Georgia. “I couldn’t drink enough from the well of politics and Washington,” Ms. Woodruff said. But the women who worked on Capitol Hill warned her against pursuing a career in government. “‘You’re going to end up the coffee girl,’” she recalled them telling her.

One of her professors at Duke University suggested journalism. She worried she wasn’t a strong enough writer to be a newspaper reporter, so she applied to television stations. During a job interview at an ABC affiliate in Atlanta, she said, the news director told her, “With legs like those, how could I not hire you?”

Her initial role? “I was the coffee girl,” she said.

A year later, she asked for an opportunity to report stories. “We already have a woman reporter,” her boss said, according to Ms. Woodruff. He then offered her something else — weekend “weather girl,” a job she was allowed to take on as long as she continued tending to her duties as the newsroom’s secretary.

She heard that WAGA, the CBS affiliate in Atlanta, was hiring. “I was amazed at her background, between Duke and working on the Hill,” said Bob Brennan, who was the station’s news director. “I thought, ‘What the heck is she doing weekend weather for?’”

He hired her to cover the Georgia State Legislature, teaming her with an experienced cameraman who introduced her to the state’s power players. She was 23. Her first year on the job, Jimmy Carter, then a state senator from Plains, Ga., ran for governor and won.

Phyllis Mueller, who was one of the few women in WAGA’s news department, saw anchor potential in Ms. Woodruff. At the time, the channel’s noon newscast was struggling. Sandwiched between soap operas, it got such low ratings that the station was selling only two minutes of the available eight and a half minutes of commercial time, Ms. Mueller said. With so little to lose, Ms. Mueller argued to the news director, why not give her a chance to produce the newscast, with Ms. Woodruff as the anchor?

“It was said that women were not credible, that people wouldn’t believe the news if a woman read it to them,” Ms. Mueller recalled.

The station went ahead with the plan, partly because the two young women were not paid very much and there weren’t many viewers to alienate, Ms. Mueller said.

“Judy really thrived,” she said. “The camera really liked her. She was relaxed with someone talking into her ear while reading, was open to taking direction and was great at thinking on her feet.”

The program became the best-rated show in its time slot, Ms. Mueller said, and the station made Ms. Woodruff an anchor of its evening newscast as well.

In 1974, during a job interview in New York with an executive from NBC News, Ms. Woodruff was told she needed to work on getting rid of her Southern accent, she recalled. She returned to Atlanta and found a voice coach in the Yellow Pages. Before she could begin lessons, the executive called her. She was hired in early 1975 to report from the NBC News bureau in Atlanta.

Ms. Woodruff’s dispatches began to appear on “NBC Nightly News” and “Today.” By the middle of the year, she was urging the network to pay closer attention to Mr. Carter, who was running for president but lagging in the polls, and she filed occasional stories on his campaign.

After Mr. Carter won the New Hampshire primary in 1976, NBC gave the assignment to more experienced reporters — men, obviously. Ms. Woodruff stayed on as a junior reporter, a role that nonetheless made her one of the so-called boys on the bus, a phrase used at the time for the reporters covering presidential campaigns, a group that included Sam Donaldson of ABC News.

While reporting on Mr. Carter in Steubenville, Ohio, Ms. Woodruff caught the eye of her future husband, Albert Hunt, who was then a national politics reporter for The Wall Street Journal. “I did something that they would drum you out of polite society if you did today,” Mr. Hunt said. “I got on the bus and I said to Sam Donaldson, ‘Sam, who is the blonde with the great legs?’”

Ms. Woodruff and Mr. Hunt formally met at a softball game in Plains, where Mr. Carter’s campaign staff members competed against the reporters, according to her 1982 book, “This Is Judy Woodruff at the White House.” She evaded the smitten Mr. Hunt until after Mr. Carter’s inauguration. They were married in 1980.

With Mr. Carter in the White House, Ms. Woodruff became a White House correspondent for NBC News. “It was clear to everyone that she just knew more about Jimmy Carter than anyone else in Washington,” said Tom Brokaw, who covered the White House for NBC before eventually becoming the network’s evening anchor.

She was ambitious and competitive. “When an important news event occurs, I want to be the one NBC wakes in the middle of the night to cover it,” she wrote in her memoir. But she still helped the careers of other female journalists, said Andrea Mitchell, who joined NBC’s Washington bureau in 1978 and is now the network’s chief Washington correspondent and foreign policy correspondent. “We’re the same age but she had seniority, and she made room for me and looked for ways for me to shine,” Ms. Mitchell said.

On March 30, 1981, Ms. Woodruff was among the White House pool reporters when President Reagan was speaking at a luncheon at the Washington Hilton. As he was coming out of the building, she stepped toward him to ask a question when she realized she had gotten separated from her camera crew.

“Then I heard the pop, pop — pop, pop, pop, pop,” she wrote in her memoir. “In that instant of realizing that the explosions I had heard were a fusillade of gunshots, my heart froze.”

She was pregnant at the time. For a moment she feared she was in the line of fire.

As the wounded president was taken from the scene, Ms. Woodruff had to find a phone, so that she could call in her report. Another reporter beat her to a pay phone in a nearby drugstore. She ran into an office building and begged a receptionist to let her make a call.

In 1983, she scored an interview with George P. Shultz, the secretary of state. “We prepared for weeks,” she said, “and the piece ran at three minutes.” Realizing that the trend of shorter segments on network news shows would continue, she left NBC for PBS, becoming the chief Washington correspondent for “The MacNeil/Lehrer NewsHour,” the program anchored by Robert MacNeil and Jim Lehrer.

“My friends said, ‘You’re crazy. How could you leave a network?’” Ms. Woodruff said. “But I wanted more time and more serious topics.”

She was still at PBS in 1993 when she attended a dinner party at the home of Katharine Graham, the former publisher of The Washington Post. Tom Johnson, then the president of CNN, was one of the guests.

“By the end of that night, I knew I had to get Judy Woodruff,” he said “I took every opportunity before, during and after dinner to recruit her. I don’t think I ever did more to persuade a person, with the exception of convincing my wife to marry me.”

After meeting with the CNN owner, Ted Turner, Ms. Woodruff agreed to join CNN as the co-anchor, with Bernard Shaw, of the political talk show “Inside Politics.”

In 1998, tragedy struck. The oldest of her three children, Jeffrey Hunt, who had been born with a mild form of spina bifida, went to the hospital for a routine-seeming surgery. The operation went awry, leaving him in a coma for more than three months. He was no longer able to walk, and suffered impaired vision, speech and short-term memory.

“I just fell apart,” Ms. Woodruff said.

She continued to work as she cared for her now wheelchair-bound son and her other children. “The doctor told me, ‘You need to be who you are and do what you do to be the best possible mother,’” she said.

Ms. Woodruff and Mr. Hunt worked with schools so that Jeffrey could continue his education and he graduated from college. He now lives about 40 miles from his parents, in a group home on a school campus where he has a job and an active life, Ms. Woodruff said.

Mr. Shaw retired in 2000, and Ms. Woodruff continued anchoring “Inside Politics” until 2005. The next year she returned to PBS, making documentaries and filing reports for its nightly news hour, which became “The NewsHour With Jim Lehrer” after the 1995 retirement of Mr. MacNeil. In 2013, after Mr. Lehrer had retired, Ms. Woodruff and Gwen Ifill, a former political reporter at The Washington Post and The New York Times, were named the co-anchors and managing editors of “PBS NewsHour.” PBS noted at the time that their appointment marked “the first time a network broadcast has had a female co-anchor team.”

“When she was anchoring with Gwen, there was a kind of power in their professionalism, restraint and authority that was incomparable, just incomparable,” said Mr. Goldberg, the editor of The Atlantic.

Ms. Ifill was diagnosed with cancer at the end of 2015. Few people besides Ms. Woodruff knew the extent of her illness. “She was fighting cancer almost entirely in privacy, with great fortitude,” she said.

Ms. Ifill died on Nov. 14, 2016, less than a week after Donald Trump was elected president. “I was so shattered by her death, and we were all trying to deal with this massive news story,” Ms. Woodruff said.

She took over as sole anchor, the job she will relinquish at the end of the year.

On Tuesday night, hours after the polls had closed, many of the key races were too close to call. The special edition of “PBS NewsHour” was supposed to wrap up at midnight at the latest, but Ms. Woodruff, putting on her managing editor hat, asked for more time.

The studio powered down at 12:30 a.m. After a broadcast that lasted six and a half hours, Ms. Woodruff tossed the mostly uneaten takeout soup into a garbage can and stepped away from the anchor desk. She got into her white Mercedes-Benz S.U.V. and drove the 20 minutes from Arlington to Washington. In her apartment, she said, her husband was asleep. She tiptoed into the bathroom and washed off her TV makeup.