Television's most popular morning show also took the wraps off a rebuilt studio in Manhattan's Rockefeller Center, and began broadcasting in high definition.
NBC worked overtime to welcome Vieira into the "family" of a TV show dependent on the personal connection felt by pajama-clad viewers. Her children mocked her cooking, a picture was flashed of a dolphin kissing her and "Nightly News" anchor Brian Williams popped by with a bouquet of flowers.
The longtime CBS newswoman and recent host on daytime's "The View" replaces Katie Couric, who left to anchor the "CBS Evening News." NBC has a lot riding on Vieira's successful transition to "Today," which is on a 10-year ratings winning streak and is TV's most profitable show.
Vieira admitted to nervousness and showed off the good-luck bracelet her husband and teenage children gave her the night before. Introducing weatherman Al Roker, she noted she had a hamster named Al growing up.
Vieira also flashed a copy of People magazine photo of Lauer on a beach this summer, holding his daughter's hand and showing off rippling abs. Lauer showed off an old Esquire where Vieira flashed her legs.
She then muffed the wording on her first "throw" to a commercial, tossing the magazine over her shoulder.
Vieira won't be completely abandoning the bawdy personality that came through during her years on "The View."
"I'm going to be 'the broad' in broadcasting," she said.
NBC briefly profiled Vieira, her husband and three children, showing clips from the beginning of her news career in Providence, R.I. The network also had gathered the students and teachers from Vieira's grammar school in Providence for a live shot.
Her first serious duty was interviewing NBC's Washington bureau chief, Tim Russert, who had traveled north for the special day. They talked about President Bush's speech on the Sept. 11 terrorist attacks and the political response.
After Vieira asked about whether the Democrats needed a specific plan for Iraq, the friendly Russert said: "That's the magical question. You have put your finger on it."
"Today" rebuilt its studio for the switch to high-def, making it as bright as a sunlit morning. The hosts sat behind a gleaming white desk, and Vieira interviewed Russert while both sat in spotless white easy chairs.
The show ran excerpts of Lauer's interview with Debra LaFave, the Florida teacher who had sex with a 14-year-old student. In its popular segment playing up to an on-air wedding, Vieira scooped a finger-full of frosting and smeared it on Lauer's nose.
Vieira could be forgiven the need to take a few deep breaths before the camera's red light went on Wednesday, given the show's importance to the network.
"It's just a great ensemble of people," she said recently. "I'm like the aunt who is coming in to the family. I'm going to not at this point go under the radar scope but just fit in and feel my way. I'm not going to go in there with a hammer."
Vieira expects her alarm clock to ring about 3 a.m. each weekday morning, and she'll go to bed each evening between 8 p.m. and 9 p.m. She said her children won't mind having the run of the house late.
She will continue as host of the syndicated "Who Wants to Be a Millionaire," and said she's gotten a head start by taping 60 of the new season's 175 new shows.
NBC is owned by General Electric Co.