Rebecca Blumenstein, the president of editorial for NBC News, and Carrie Budoff Brown, the network’s senior vice president of politics, thanked Mr. Todd in a memo and said Mr. Todd would continue at NBC as chief political analyst.

“Through his penetrating interviews with many of the most important newsmakers, the show has played an essential role in politics and policy, routinely made front-page news, and framed the thinking in Washington and beyond,” the memo said.

Ms. Welker, 46, is a longtime NBC stalwart. She was an intern for “Today” in 1997 and has been working for the network full time since 2010. She began covering the White House for NBC a year later and has covered presidents abroad in Belgium, England, Austria, Poland and Japan. In 2020, she was widely praised for her moderation of the final presidential debate between President Donald J. Trump and Joe Biden.

Mr. Todd took over “Meet the Press” for David Gregory, who became its moderator after the death of Tim Russert in 2008. Viewership of the show has slid significantly in the years after Mr. Russert’s death.

In 2014, Mr. Todd launched “MTP Daily,” the first daily installment of “Meet the Press,” which aired on MSNBC until last year. MTP Daily moved to NBC News Now, the network’s advertising-supported streaming platform.