The 26-year-old Norris won the title by two points from Red Bull's Max Verstappen, who took his eighth win of the year, one more than the Briton and his McLaren teammate, Oscar Piastri.
McLaren was always in control of the tense race, even though Verstappen looked set for victory from the first lap, as Piastri finished second and was in a position to help Norris if needed.
Norris became the 11th British F1 World Champion at the end of his seventh season in F1, a year in which he started slowly but grew stronger in the second half.
And this is McLaren's first Drivers' and Constructors' title double since 1998.
A happy Norris said, "I hadn't cried in a while, and I didn't think I would, but I did."
"I mean, it feels great, now I know how Max feels. I want to congratulate Max and Oscar, who have been my two biggest competitors throughout the season."
"It's a pleasure and an honor to race against them both, and I've learned a lot from them both.
"I enjoyed it, and it's been a long year, but we did it, and I'm very proud of everyone."
Although McLaren has been the fastest car on balance this season, Norris's championship will gain even more credibility from the fact that he won it while facing a strong challenge from Verstappen, who is widely considered the best driver of his generation.
Norris broke down in tears in his car during the slowing down lap as he received congratulations from his team and thanked them and his family for allowing him to achieve his lifelong dream.
Highlights from the race included:
- Norris and McLaren's calm and controlled drive to the title
- The battle between Norris and Red Bull's Yuki Tsunoda, with the Japanese driver attempting to help Verstappen mid-race, even posing a small threat of a penalty for the McLaren driver.
- Verstappen's resounding victory crowned perhaps the most impressive year of his career.
McLaren and Norris faced pressure
When the race finally began after a nervous weekend for McLaren, the pressure on the team was immense, having endured two difficult races in the preceding Grand Prix. A double disqualification in Las Vegas, followed by a flawed strategy that handed Verstappen victory in Qatar, had raised the stakes for McLaren at the end of a year in which they won the Constructors' title with six races remaining.
Norris ran cautiously at the start, avoiding the onslaught of Verstappen, as the Dutchman aggressively defended his lead from pole position on the run to the first corner.
Halfway through the lap, Piastri accelerated around Norris's outside on the long left-hander of Turn Nine, a clear strategic move to give the Australian the win over Verstappen.
Piastri was on hard tires, and Verstappen and Norris were on medium tires, so the plan was to run long and give Red Bull something to think about and reduce the risk of falling back down the field at Norris's expense.
Norris had to fight Ferrari's Charles Leclerc for third place, but he always remained in control.
And after Norris's second tire stop, the British driver closed in on Piastri in the final laps, demonstrating Leclerc's two-stop strategy.