Jim Lehrer, a lifelong newsman — don’t call him a “journalist”; too pretentious, he says — knew this day was coming. He’s been preparing for it, and preparing the program that has borne his name for more than a generation, too, for several years.

Still, the news about one of America’s most respected newsmen on Thursday was something of a surprise: After 36 years as the calm, steady, understated anchor of PBS’s nightly “NewsHour,” Lehrer says he’s pulling back, if not entirely slowing down. He’ll anchor his last “NewsHour” on June 6, after roughly 8,000 broadcasts and a few zillion newsmaker interviews.

Befitting the tone of his program, he’s unsentimental about the whole thing. “We’ve got a great team in place,” he said Thursday, sitting in his Arlington office, crammed with a formidable collection of bus memorabilia (a hobby that harks back to his father’s failed effort at running a bus company). “I’m proud of this — I’m on one of the most graceful glide paths to departure that anyone could have set up.”

In an age of eroding attention spans, Lehrer, 76, has been a throwback to the more deliberate Cronkite Age of anchoring. He still writes his copy and still acts as executive editor of the program, overseeing its daily lineup of stories and talking-head interviews. The program (and companion Web site) seems like an extension of his personality: modest and unflashy, with a grown-up’s take on the day’s major events.

For his part, Lehrer never did the fashionable anchor thing. No wading in hip-deep floodwater. No jetting off to the hurricane or royal wedding. While commercial newscasts changed — more health news! more soft features! more Kardashians! — “NewsHour” has evolved. Slowly.

“I’ve always seen this as a preserve of serious news,” Lehrer said. “It’s not magic, and it’s not saintly. We’ve been doing it for 36 years, and we’ll continue doing it. Others won’t. That’s their problem.”

Lehrer’s longtime collaborator and partner in “NewsHour’s” production company, Robert MacNeil, offers an even blunter take: “The joke we’ve always had is that we have the courage to be boring, to do things that other people in TV considered boring. Our feeling is that we don’t want to be assaulted by TV, or shouted at, and neither do our viewers.”

Lehrer set his succession in place about 18 months ago. He said he asked himself, “How do I depart in a way that protects the institution, prevents unpleasantness among the people involved and keeps the continuity?” Answer: He took his name off his show, a shockingly unegotistical move designed to rebrand the program for the post-Lehrer era. Now, instead of “The NewsHour with Jim Lehrer,” it’s “The PBS NewsHour.”

The name change coincided with a bigger anchoring role for the journalists — uh, newspeople — who will inherit Lehrer’s mantle: Gwen Ifill, Judy Woodruff, Jeffrey Brown, Ray Suarez and Margaret Warner, who will continue anchoring on a rotating basis. Lehrer will remain involved in the program’s “editorial direction.”

Lehrer started as a newspaperman in Dallas 52 years ago after three years in the Marine Corps. He sold his first of nearly two dozen novels — a caper called “Viva Max!” that imagined a Mexican general with the ambition to retake the Alamo. When Columbia Pictures bought the book for a movie starring Peter Ustinov in 1969, Lehrer pocketed a $40,000 advance and thought he was on his way to becoming a full-time novelist.

He quit his newspaper job — and landed back in the news business three days later, mentoring a start-up news program on Dallas educational station KERA. Soon, the fledgling PBS came calling, hiring him as coordinator of news and public affairs, a job that involved slaloming around the Nixon administration’s little-disguised hostility toward public broadcasting’s news coverage. One of the programs he coordinated was a news show co-anchored by an erudite former BBC foreign correspondent named Robert MacNeil.

MacNeil and Lehrer first became a team on air in 1973, when PBS broadcast the Senate Watergate hearings. The hearings, carried live and repeated each night, became a huge and unexpected hit, and MacNeil and Lehrer emerged as its low-key, Emmy-winning stars.

PBS knew it had to find something for the pair, apres Nixon. In October 1975, it began distributing the half-hour “Robert MacNeil Report,” with Lehrer as the Washington correspondent. Within a year, Lehrer became co-anchor and the program was redubbed “The MacNeil/Lehrer Report.”

The two men have remained close friends ever since their children, now adults, attended the same kindergarten. The families lived within blocks of each other in Bethesda, and the pair carpooled to WETA’s office in Shirlington each day. They’re so close, Lehrer said only semi-facetiously, that they know each other’s bank balances.

It’s a testament to the duo’s enduring power that regular viewers still refer to the program by its original name (or just “MacNeil/Lehrer”). But, MacNeil made a clean break in 1996 (he has contributed occasionally since then).

Lehrer doesn’t call what he’s doing next retirement or even semi-retirement. He’ll “read a stack of books” and plans to write a few more, too. He’ll return to the “NewsHour” every Friday to moderate the panel of journalists who analyze the week’s events. And there are six grandchildren he’d like to spend some time with.

He’s uncertain, however, if he’ll moderate another presidential debate. He’s done 11 of them, over five presidential cycles (his nonfiction account of those debates, called “Tension City,” will be published in September), but that might be it.

“Anyone who does it has to keep up,” he said. “If I’m invited, I might say no, just on the grounds that I’m not following [events] as closely as before.”

What won’t change, promises the onetime Marine, is his signature program’s discipline, its proud lack of flash and glitz. For years, Lehrer’s operating philosophy has been what he calls “the Skivvy-Shirt Rule.” Which means? “You comb your hair, knot your tie and don’t do anything to distract the viewer from the news,” he said. “You don’t want anyone thinking, ‘He’s wearing his skivvy shirt.’ ”

The newsman lets that sink in. “You want them to pay attention to the news,” he said.