When Jon Stewart exits “The Daily Show,” he will join a small group of elite hosts who changed the tone and importance of talkshows. Here are a dozen others (in chronological order) whose influence was long-lasting.

Steve Allen

He created the template for late-night talk with “Tonight Starring Steve Allen,” which ran from 1954-57 on NBC. There was a desk, chatter with multiple guests, comedy, and music guests, including Elvis Presley — even though Allen hated rock ‘n’ roll. Allen did man-on-the-street interviews and had a gallery of comic players, including Tom Poston and Don Knotts.

Jack Paar

As more TV sets were sold in the 1950s, more people tuned in for late-night TV. Jack Paar put late-night on the map when he took over “Tonight,” partly because he generated more publicity than anyone else at the time. He wept on the show, he broadcast from the new Berlin Wall, and he walked off mid-broadcast after NBC censored a (mild) joke about a British “water closet.” He returned three weeks later, after NBC apologized. Paar’s “I kid you not” became a national catchphrase. The show ran 105 minutes, and Paar hosted five nights a week — a workload far in excess of current hosts.

David Susskind

Though the least well known of this group, he brought gravitas to the format, via serious conversations with his guests. “Open End” (1958) ran three years without a firm wrap time: The show ended when he and his guests ran out of conversation. In 1961, it was syndicated in a two-hour format. The subsequent “The David Susskind Show” (1966-86) followed the same setup by addressing things generally unseen on most other late shows, including Vietnam, transgenders and civil rights.

Johnny Carson

For many, he remains the gold standard, with a 30-year run. He began with “The Tonight Show” in 1962. A decade later, the N.Y.-based “The Tonight Show Starring Johnny Carson” moved to L.A., a radical shakeup. But he retained the Carnac the Magnificent, Floyd Turbo and Aunt Blabby routines and made the opening monologue a cornerstone of yakkers. By the time he wrapped in 1992, he was a bigger star than most of his guests.

Merv Griffin

From 1965-86, he hosted “The Merv Griffin Show,” which was syndicated, moved to CBS, then syndicated again. On “SCTV,” Rick Moranis perfectly captured his style of leaning in, touching his guests and laughing genially at everything they said. But he could also push the envelope, booking guests like Abbie Hoffman, Bertrand Russell or the Village People. Despite his 21 years in talk, he is best remembered for creating “Jeopardy!” and “Wheel of Fortune” and owning the Beverly Hilton.

Dick Cavett

From 1968-1996, he fronted shows of varying lengths on at least five networks. He was considered the intellectual alternative to Johnny Carson and Merv Griffin; Cavett seemed like he was having a conversation with guests rather than interviewing them. His lineup was diverse, including Janis Joplin, John Kerry, writer Mary McCarthy and Groucho Marx.

David Letterman

He simultaneously hosted a show and spoofed the whole setup. In his 33 years in late-night, he seemed to get grouchier, which endeared him even more to his fans. He also started franchises like Stupid Pet Tricks and his Top 10 lists, which were the subject of legal wrangles when he moved from the post-Carson slot on NBC (1982 to 1993) to the 11:30 hour on CBS (1993-2015).

Joan Rivers

Here was a radical concept: A woman hosting late-night! After decades of only three networks, Fox started a fourth and invited Rivers to host a 1986 late-night show as one of its branding centerpieces. She earned the gig thanks to her frequent guest-hosting of Carson’s show, though it caused a freeze between them that lasted until his death. “The Late Show” ran October 1986-May 1987. And while women have thrived as morning and/or daytime hosts, women are still rare in late-night.

Arsenio Hall

The show ran 1989-94 in syndication. He was a little hipper and edgier than his competition, and the audience was younger. Hall also was a pioneer when Bill Clinton came on his show in June 1992, playing “Heartbreak Hotel” on the saxophone. Purists in D.C. were horrified, but Clinton won the presidency, and politicians soon learned that talkshows were a great way to reach the people. Hall revived the show in 2013, and it lasted one season.

Charlie Rose

Starting in 1991, he hosted his self-titled show, tapping into his background in journalism and politics for interviews. With his furrowed brow and rephrasing questions “to make sure I understand,” it’s clear that this is for thoughtful talk, but not chit-chat. In the world of guest bookings, it’s considered a supreme compliment if Rose books you for the entire hour.

Jay Leno

He smoothed down the edginess of his standup routines, and proved a popular host of “Tonight” from 1992-2009 and again 2010-14. In his monologues he targeted the likes of the O.J. Simpson trial and the Bill Clinton sex scandal. Leno inadvertently shone a spotlight on the backstage workings of a talkshow when the public learned of the intense battles for host-dom with former pal David Letterman and then again with Conan O’Brien.

Conan O’Brien

Audiences, critics and NBC were unimpressed when Conan O’Brien started hosting “Late Night” in 1993. But they all began to like him for the qualities they’d been skeptical of: his off-the-wall humor, self-deprecatory style and his accessibility. When Letterman retired in 2015, O’Brien became TV’s most senior host, with 22 years: 1993-2009 “Late Night,” then “The Tonight Show” 2009-10, and “Conan,” from 2010 to the present.