Craig Melvin, the veteran NBC News host, will succeed Hoda Kotb as an anchor of the network’s flagship morning show, “Today,” the company announced Thursday morning.

Mr. Melvin will start in the new role, teaming with Savannah Guthrie, on Jan. 13.

The position, one of the most prominent in television news, opened after Ms. Kotb, who has been at the network for more than two decades, announced in September that she would step down early next year. Ms. Kotb, who will remain as a contributor to the show, said at the time that she wanted to spend more time with her young children, and that it was “time to turn the page on what has been a dream book, a dream quarter-century.”

Ms. Kotb, 60, will take her final turn as co-anchor of “Today” on Jan. 10.

By selecting Mr. Melvin, 45, network executives chose to go the steadiest route possible. He has been the news anchor of “Today” since 2018, frequently joining Ms. Guthrie and Ms. Kotb on the set at some point in the 7 a.m. hour. He is also a co-host of the show’s 9 a.m. hour, and used to be an anchor of the weekend edition of “Today.”

Mr. Melvin also was an anchor on MSNBC before leaving his daily 11 a.m. show on the cable network two years ago.

“Dreams do come true,” he said in an interview before the news was announced on “Today.”

“As someone said to me, this is an obit job,” he continued. “When you die one day, this is the first thing that gets mentioned in an obituary after it mentions you were a husband and a father.”

Mr. Melvin said he found out about his selection several weeks ago. (NBC News executives kept it under wraps until after the presidential election.) Ms. Kotb said in an interview that it was such a secret that they had to develop a code term in order to toast his success, since so few people knew of it. The code? “Let’s Go Mets.”

They coined it during “the height of Mets mania,” Ms. Kotb said, adding that she invoked it repeatedly as the team was going through an improbable playoff run.

“It was fun to see his face,” she said, recalling each time she said it. “He looked like a kid on Christmas, getting what he wanted.”

Ms. Guthrie said she and Mr. Melvin toasted his appointment when they were in Miami to attend a Taylor Swift concert with their families last month. Ms. Guthrie said the transition would be “seamless.”

“He’s the classic jack-of-all-trades that you really need in this job,” she said. “He can do hard news, he can do the fun stuff, and doesn’t take himself too seriously.”

Ms. Kotb underscored his versatility as well.

“He’s a serious journalist, but he’s also good company,” she said. “Being good company matters at this hour. Being good company when you’re at home having a bowl of cereal and coffee matters.”

“Today” is a significant driver of revenue for NBC News, and the show has been on a roll recently. “Today” averaged 2.9 million viewers last week, besting ABC’s “Good Morning America” in total audience for a second consecutive week. The show has also eclipsed “G.M.A.” in the ratings demographic most important to advertisers — adults under the age of 54 — for 65 consecutive weeks.

When Mr. Melvin takes over anchoring duties, he will continue hosting at 9 a.m., keeping him on the air for three consecutive hours. He hosts that hour with Al Roker, Sheinelle Jones and Dylan Dreyer.

NBC also said the fourth hour of “Today,” at 10 a.m., would continue to be helmed by Jenna Bush Hager after Ms. Kotb vacated her hosting position. Ms. Bush will host the show with a series of rotating hosts until a permanent successor is announced.

“There’s a reason that the ‘Today’ show has been on the air for more than 70 years,” Mr. Melvin said. “The fact that people continue to allow us in their homes when they have so many options now? I’m just honored to be part of that. I’ve been trying to wrap my head around it, but I’m just gobsmacked.”