With just one departure, “Saturday Night Live” is losing its excitable “Weekend Update” city correspondent, Stefon; its frenetic incarnations of James Carville, Al Pacino, Vincent Price and Julian Assange; and any number of unctuous, self-satisfied game-show hosts.

All of which is to say that Bill Hader, an eight-year veteran of “Saturday Night Live,” will be leaving that NBC late-night franchise.

“It was a hard decision, but it has to happen at some point,” Hader said in an interview. “It got to a point where I said, ‘Maybe it’s just time to go.’ ”

Hader, 34, joined “SNL” as a featured performer in the fall of 2005 and was promoted to a full cast member the following year. He quickly became known for his offbeat celebrity impersonations as well as portrayals of original characters like Stefon, a breathless aficionado of obscure New York nightclubs, and Vinny Vedecci, an Italian talk-show host.

Last year, Hader (who has appeared in “Superbad,” “Tropic Thunder” and “Men in Black 3,” among other films) became the rare “Saturday Night Live” cast member to be nominated for an Emmy for supporting actor in a comedy series.

Lorne Michaels, executive producer of “Saturday Night Live,” recalled the first time he saw Hader perform at a comedy show in Los Angeles, where he was reminded of “SNL” stars like Dan Aykroyd.

“In terms of intelligence and talent, he was in that same tradition,” Michaels said in a telephone interview. “He was so completely committed to the art of it and enough a student of it that there’s something strikingly original. He didn’t explode onto the air, but gradually he found his voice, and that became a huge thing.”

While any loss at “Saturday Night Live” is bittersweet for the show, Hader’s departure could be part of a larger exodus of established talent from the “SNL” roster.

Seth Meyers, a head writer of “Saturday Night Live” and the anchor of its “Weekend Update,” will depart next year to replace Jimmy Fallon on NBC’s “Late Night” when Fallon takes over “The Tonight Show” in February.

Fred Armisen, who has been with “Saturday Night Live” since 2002, could also be in question as he focuses on outside projects like “Portlandia,” his IFC comedy with Carrie Brownstein. That show is also produced by Michaels, as “Late Night” is and “The Tonight Show” will be.

Jason Sudeikis is something of a perennial uncertainty. Last summer he indicated he was looking to explore options beyond “SNL” but ultimately returned.

Asked if Armisen and Sudeikis had made up their minds, Michaels said, “I don’t think so. I think they’re making their decisions and we’ll know soon enough.”

Michaels added, “I’ve said what I wanted to say to both. You never keep anybody there who doesn’t want to be there, and there is a right time to leave, but it’s more about where they are in their lives.”

Armisen declined to comment for this article. A press representative for Sudeikis declined a request for comment.

Hader’s contract at “Saturday Night Live” expired in spring 2012, but he was persuaded to stay on for an additional season. In February, he told Michaels that he was ready to move on, he said. “I’d heard stories that you get very emotional in those conversations,” he added, “and I’ve had other people tell me, ‘Oh, I cried.’ I didn’t, but I did think I was about to faint.”

Hader said his decision was motivated partly by seeing friends like Andy Samberg and Kristen Wiig leave last season, and partly by a desire to move his family to Los Angeles. His wife, Maggie Carey, is getting busier with her filmmaking career, which includes the forthcoming comedy “The To Do List” (which she wrote and directed, and in which Hader appears). Meanwhile Hader said he had worked on three live-action features and four animated films during the current season of “SNL” alone.

Whoever remains with “Saturday Night Live,” Hader said it would be in good hands as newer cast members like Taran Killam, Vanessa Bayer and Kate McKinnon come into their own.

“There’s a new sensibility happening,” Hader said, “and if it isn’t totally apparent on the show yet, I see it on Wednesdays at the table reads.”

At those sessions this year, Hader said, “I found myself looking up and watching the new people do their sketches. I like watching Kate McKinnon do something — there’s a joy in seeing a new move from somebody and going, ‘Oh, she can do that.’”