The 26-year-old Briton, winner of the past two F1 races in Hungary and the Netherlands, broke the news to McLaren employees at a friends and family day at the Woking factory on Saturday.
McLaren said there was also a multi-year option to commit beyond 2030, and Norris had been gifted an MCL39 car from last season when he became the team's first drivers' champion since Lewis Hamilton in 2008.
Speaking earlier to reporters, Norris said the deal came at a perfect time for team morale and motivation, but said the figures seen in some media speculation were wide of the mark.
"At the minute there's really no reason to want to even put a thought into somewhere else," he said. "I kind of want my whole career to be with McLaren because I'm happy here and I don't want to change.
"I want to fight with McLaren even when things are not going well, and I want to win with McLaren when things are going amazingly well.
"So yeah, I'll be very, very happy at the end of my career to say that McLaren was the only team I've been with."
Norris made his McLaren F1 debut in 2019, after joining in 2017 as a test and simulator driver, and has now won 13 grands prix with the reigning constructors' champions, as well as 18 poles.
"This extension gives us important continuity and reinforces our confidence in the direction we are taking together," said team principal Andrea Stella.
"With him and (Australian) Oscar (Piastri), we know we can count not only on one of the strongest partnerships but also on one of the most united and close-knit teams in Formula One."
Some media reports have suggested the new deal would put the Briton third in Formula One's pay rankings, behind only Red Bull's Max Verstappen and Ferrari's Hamilton.
One speculated that Norris's new salary could be about 60 million euros ($A97 million) a year.
"I feel like I should earn as much as that," he grinned in response to a mention of what four-time champion Verstappen and seven-time champion Hamilton might be on.
"But it's certainly not close to the figures that I've been seeing online, sadly.
"Of course it's a bit more, as it is with any job when you kind of extend and do those things, but it's certainly not close to the level of Lewis or Max, which in a way it shouldn't be, because I've not achieved as much as what they've achieved in their careers."
