"I've thought a lot about what it means to succeed somebody like Tim Russert," Gregory told viewers. "I'm not Tim. But along with this great team, I can just work real hard to make him proud."
A ratings leader with enormous influence, "Meet the Press" brings Gregory "one of the greatest jobs there is," he said in an interview after the broadcast. "It's a place where accountability reigns, where leadership is explored and where people come to understand how the government works and try to understand the important issues of the day."
In addition to his "Meet the Press" responsibilities, Gregory will be a regular contributor for "Today" and continue as a backup anchor. He will also continue as a regular contributor and analyst on MSNBC and for NBC News coverage of special events, the network said.
A Los Angeles native who joined NBC News in 1995, Gregory was MSNBC's chief anchor on Election Night and during general election debates, and has hosted an hourlong political show weekdays on MSNBC.
Sunday's announcement came after months of speculation about who would be chosen, with unconfirmed reports surfacing last week that NBC had settled on Gregory. Until then, Andrea Mitchell, Chuck Todd and Gwen Ifill were also among those thought to be contenders.
The choice of Gregory was "a natural decision," said NBC News president Steve Capus, explaining "he's got a full skill set" as a broadcast journalist.
Then why the delay in making the transition?
"This is about the first chance we've had to focus on it," Capus replied. He reviewed the past six months, with the shock of Russert's death followed by NBC's extensive coverage of the Beijing Olympics, then the political race and election night.
"Through all that, we knew we had Tom (as a substitute), and we knew we had David," Capus said.
NBC also announced Sunday that Betsy Fischer, the program's executive producer since 2002, will stay on for a period described as "several years."
Fischer, whose career at NBC News began with an internship at "Meet the Press" while in college, has been with the program for 17 years.
Asked how it will change with Gregory as host, she said: "You want to play to the strengths of the host, and we'll come up with some innovative things. But the changes will be seamless."
"Meet the Press" has the cachet of being network TV's longest-running series, having premiered in November 1947.
It dominates the Sunday morning political landscape. During November, it averaged 4.5 million viewers each Sunday. ABC's "This Week" with George Stephanopoulos had 3.5 million viewers, CBS' "Face the Nation" with Bob Schieffer averaged 3.1 million viewers, and "Fox News Sunday" with Chris Wallace had 1.5 million viewers, according to Nielsen Media Research.