NBC moved swiftly to get Vieira, 52, in place one day after Katie Couric announced she was taking a job as "CBS Evening News" anchor. It's the first on-air personnel change in a decade on television's dominant morning program.
Vieira has spent the last nine years on the daytime chat show "The View" but also has an extensive news background, including a stint on "60 Minutes."
"If you were building a morning show host from scratch, she would be the prototype," said Jeff Zucker, CEO of the NBC Universal Television Group. "She has the perfect combination of news background and talk background. She's got intelligence, grace, humor and those are the qualities you look for when you're trying to fill this role."
Zucker began his courtship of Vieira last October, when he called and asked to give her a ride from "The View" studio to where she was taping shows as host of "Who Wants to Be a Millionaire." It's normally a three-minute ride on Manhattan's upper West Side.
Zucker showed up in a black SUV with tinted windows. Aware that Couric was considering leaving, he asked Vieira to think about whether she wanted to get into morning television.
She met Lauer at his apartment for dinner in December. "It was like going out on a blind date and finding out you really like the guy," she said.
With chemistry as important as ability on morning TV, Lauer and Vieira tried to display it at Thursday's news conference announcing their pairing, which will begin in September. He flashed mock anger when Vieira interrupted one of his stories.
"Can I tell the story?" he said. "Is this going to happen? I've been going through 10 years of this."
Vieira said she expects to leave "The View" at the end of next month.
NBC chose Vieira over several internal candidates, including weekend "Today" anchor Campbell Brown, newswoman Natalie Morales and "Today" newsreader Ann Curry. Brown and Morales had subbed for Couric on "Today" while she was on vacation at the end of last month.