Jim Lehrer, an understated television newscaster who co-founded what is now “The PBS NewsHour,” which he anchored for 36 years, and who was dubbed the “dean of moderators” for presiding over 12 presidential debates, died Jan. 23 at his home in Washington. He was 85.

PBS announced his death but did not provide further details. He had a heart attack in 1983 and heart valve surgery in 2008.

Mr. Lehrer began his career as a newspaper reporter in Texas before switching to broadcast journalism in the early 1970s. He came to Washington in 1972, quitting his first job over budget cuts at the fledgling Public Broadcasting Service.

After moving to WETA-TV, based in Arlington, Va., he began covering the Watergate hearings in 1973 with fellow reporter Robert MacNeil.

In 1975, they teamed up to launch “The MacNeil/Lehrer Report,” a 30-minute broadcast that initially focused on a single topic each night.

The two anchors offered contrasting styles: The Canadian-born MacNeil, a onetime correspondent with NBC and BBC, had an air of urbanity, with a distinguished Mid-Atlantic accent. Mr. Lehrer, by contrast, had a windblown voice with echoes of his Kansas and Texas upbringing, and he never lost the laconic, slightly rumpled manner of the newspaper city editor he had once been.

“He did a great deal to improve my interview style,” MacNeil said of Mr. Lehrer in 1986. “I painfully learned from Lehrer that some of the most effective questions are ‘Why?,’ ‘I don’t understand,’ and ‘Could you say that again?’ His informality has eased me up a lot.”

“MacNeil/Lehrer” presented a sober approach to the news, often with experts debating complex issues in great detail. MacNeil and Mr. Lehrer were probing without being provocative. They were sometimes criticized for being bland.

“Admirers of ‘The MacNeil/Lehrer Report’ — and there are many of them,” political commentator Alexander Cockburn wrote in Harper’s Magazine in 1982, “often talk about it in terms normally reserved for unpalatable but nutritious breakfast foods: unalluring, perhaps, to the frivolous new consumer, but packed full of fiber.”

The program drew a loyal audience of several million viewers a week, often by focusing on stories that the commercial networks did not cover with as much depth, including international relations, economics, science and the fine arts.

The program grew to a full hour in 1983, making the renamed “The MacNeil/Lehrer NewsHour” the first nightly hour-long newscast on any U.S. network. The format changed to cover a wider range of stories, but with no commercials to interrupt the broadcast, MacNeil and Mr. Lehrer could deliver a solid 55 minutes of news each night.

“We started off saying to ourselves 10 years ago that it is fairly easy to produce heat, but very tough to produce light,” Mr. Lehrer told The Washington Post in 1985. “Sometimes we are criticized for . . . taking the passion out of issues. But if I am going to fail, I would rather do it that way.”

The journalists on “MacNeil/Lehrer” and its later incarnations included, at various times, such distinguished names as Roger Mudd, Charlayne Hunter-Gault, foreign correspondent Elizabeth Farnsworth, Ray Suarez, Gwen Ifill and Judy Woodruff, the current host of “The PBS NewsHour.”

When MacNeil retired in 1995, the program was renamed “The NewsHour with Jim Lehrer.” By then, Mr. Lehrer was already well established as a moderator of political debates, and between 1988 and 2012, he was the lead or only questioner at a dozen presidential debates.

He had long since adopted a policy of strict political neutrality and had not voted since 1964.

“It’s not a badge of anything. It’s just a personal idiosyncrasy,” he told The Post in 2000. “Any outside thing that gets in the way — ‘Hey, do I like this guy or not? Do I think he’s right or not?’ — is two, three, four, 10, 100 things I don’t need when I’m doing the job.”

His avuncular, nonconfrontational style won both admirers and detractors.

“He’s followed the cardinal rule of the moderator: Nobody’s tuning in to see or hear you,” ABC journalist Hal Bruno told The Post in 1996.

Media critic Jack Shafer, however, described Mr. Lehrer in a 2000 interview with The Post as “so vacant, so impassive that you can end up mapping onto him anything you want. . . . Fairness is overrated if fairness means challenging nobody.”

Mr. Lehrer was undeterred.

“If somebody wants to be entertained, they ought to go to the circus,” he told the New York Times in 2000. “My job in moderating a debate is different than if I were interviewing these men. It is their job to debate. It is not my job to debate. It is my job to facilitate their exchanges.”

James Charles Lehrer was born May 19, 1934, in Wichita to a working-class but entrepreneurial family. His father worked for the Santa Fe Trailways bus company and, after Marine Corps service in World War II, created the Kansas Central Lines, with three buses. The business went bankrupt after a year, but young Jim Lehrer would retain a lifelong fascination with bus travel.

The Lehrers moved to Texas, settling in San Antonio.

Inspired by the writing of Ernie Pyle and other World War II correspondents, Mr. Lehrer worked at his high school newspaper and studied journalism at the University of Missouri, from which he graduated in 1956.

After three years in the Marine Corps, he began working at the Dallas Morning News in 1959, drawing attention for his investigations of the John Birch Society and other conspiracy-minded groups.

He quit the paper over a dispute with the publisher and moved to the rival Dallas Times Herald, where he became a columnist and city editor. He also began writing fiction, publishing the novel “Viva Max!,” about a Mexican general’s quixotic attempt to recapture the Alamo, in 1966. It was turned into a 1969 movie starring Peter Ustinov and Jonathan Winters.

In 1970, he began working at a public television station in Dallas before moving to Washington. He retired from “The PBS NewsHour” in 2011.

After a heart attack in 1983, Mr. Lehrer gave up smoking, altered his diet and became devoted to a daily noontime nap.

He also renewed his commitment to writing, publishing more than 20 novels and several plays and memoirs. Several of his novels were mysteries, and others featured a character named One-Eyed Mack, who wore an eye patch and went from being a Gulf Coast pirate to being elected lieutenant governor of Oklahoma.

One of his later books, “Tension City” — a phrase drawn from President George H.W. Bush — chronicled Mr. Lehrer’s experiences as a moderator of presidential debates.

He called himself “truly a written-word person” in a 1995 interview with The Post. “That’s what got me into this business in the first place. The way you arrange words has always been the driving force in my life, professionally.

Survivors include his wife since 1960, the former Kate Staples, a novelist; three daughters; and six grandchildren.

Mr. Lehrer decorated his home and office with what he called “the finest collection of bus depot signs in America” and kept a working commercial bus at his weekend farm in West Virginia.

Over the years, he repeatedly turned down lucrative offers to join other networks, preferring the lower profile of PBS. He was praised by many colleagues for his uncompromising sense of journalistic integrity.

“I have an old-fashioned view that news is not a commodity,” Mr. Lehrer told the American Journalism Review in 2001. “News is information that’s required in a democratic society, and Thomas Jefferson said a democracy is dependent on an informed citizenry. That sounds corny, but I don’t care whether it sounds corny or not. It’s the truth.”

Adam Bernstein contributed to this report.