Egan Bernal became the youngest rider in 110 years to win the Tour de France after Caleb Ewan won the traditional sprint finish in Paris.
With the race leader not challenged on the final stage, 22-year-old Bernal became the first Colombian winner.
He crossed the line in the peloton, hand-in-hand with his Ineos team-mate and last year's winner Geraint Thomas, who finished second this time.
"To finish second behind a team-mate makes it OK," said Welshman Thomas.
"Two years ago I had my arm in a sling with a broken collarbone watching Chris Froome win, wishing I was riding and I would've taken second then, but it just shows how time and expectations have moved on.
"Egan is the future and when I'm 45 and old and fat and sat in the pub watching him win a 10th Tour de France I can say I told him all I know."
Thomas went into the three-week race as joint leader with Bernal but his preparations had been disrupted when he crashed while travelling at around 50mph in the Tour de Suisse in June.
He had to abandon that week-long race and then he had three minor crashes during this year's Tour.
Thomas led Bernal for much of the race but his team-mate was stronger in the final week in the Alps, and ended up winning by one minute 11 seconds, with Dutch rider Steven Kruijswijk 20 seconds further adrift in third.
"Thanks to all my team and thank you G [Geraint Thomas] for giving me the opportunity," said Bernal. "I'm the happiest guy in the world. I have just won the Tour de France and I can't believe it."
Bernal's victory is the seventh in eight years for a British-based team, after Ineos took over the ownership of the Team Sky squad earlier this year.
Bradley Wiggins became the first British winner of the race in 2012, with Chris Froome triumphing in 2013 and then claiming three in succession from 2015 before Thomas took last year's title.
Bernal is just the third Colombian to win one of cycling's three Grand Tours. Nairo Quintana won the 2014 Giro d'Italia and 2016 Vuelta a Espana, while Luis Herera won the Vuelta in 1987.
How the final stage unfolded
A largely pedestrian 60km ride from Rambouillet to Paris saw Bernal and his Ineos team-mates sipping a celebratory glass of champagne.
As the riders entered the capital city, the race crossed the river Seine via Le Pont Neuf, close to the medieval cathedral of Notre-Dame - French television chose not to show the building that was ravaged by fire in April - before the riders swept through the grounds of the Louvre.
Last year's champion Thomas was given the honour of leading the peloton through the Place de la Concorde and up the cobbles of the Champs-Elysees for the first time.
The pace increased with the passing of each 7km lap, which saw the riders swing round the Arc de Triomphe before hurtling back down the Champs-Elysees at speeds approaching 50mph before heading off back towards the Louvre.
Julian Alaphilippe, who led the race for 14 days, giving French fans hope of first home win since 1985, led the peloton on to the Champs-Elysees for the final time, trying to set up a victory for his Deceuninck Quick Step team-mate Elia Viviani, however, the Italian was nowhere as Lotto Soudal rider Ewan proved quickest in Paris.
The Australian, who timed his charge to the line to perfection, edging out Dutch rider Dylan Groenewegen to win his third stage on his debut Tour, said: "It was quite messy I went down the right, I'd been told to avoid there and it is quite bumpy but luckily I had enough speed to come through at the end."
For Alaphilippe, who finished fifth overall, there was the consolation of being named the race's most combatitive rider, while his compatriot Romain Bardet claimed the polka dot King of the Mountains jersey.
Slovakia's three-time world champion Peter Sagan won the green points jersey for a record seventh time.
Why Bernal's victory is not a surprise
The climbing specialist, who was born on 13 January, 1997 in Zipaquira in central Colombia at an altitude of 2,650m, showed his potential at last year's Tour, when he rode as a domestique to Thomas and four-time champion Chris Froome.
After pacing Thomas to victory on Alpe d'Huez and ultimately the overall title, Froome said: "He's got an amazing engine. You only have to look at what he did on Alpe d'Huez, for a 21-year-old, that's amazing.
"There is a lot in Egan that reminds me of myself when I was younger. It's great having him on the team and he brings a lot of young, new energy to the group."
He joined Team Sky for the 2018 season, after winning the prestigious Tour de l'Avenir - a stage race for under-23 riders that has seen many of its winners go on to Tour de France success.
He won the Tour Colombia and Tour of California last year before making his Tour de France debut as a domestique to Thomas and four-time winner Froome.
This year, three crashes helped Bernal arrive at the Tour as joint leader of the Ineos team, formerly Team Sky.
The first was his own, on a training ride in Andorra, and it ruled him out of May's Giro d'Italia, where he had been due to lead the team for the first time in a Grand Tour.
Froome's season-ending crash at June's Criterium du Dauphine then pushed Bernal up the Ineos pecking order for the Tour de France, while Thomas' spill at the Tour de Suisse later that month saw Bernal take over as the sole leader of that team and he went on to win the race.
After riding away from Thomas on the Tourmalet on stage 14 in the Pyrenees, he did so twice again in the Alps in the final week to position himself as Ineos' strongest rider at the Tour and secure his first Grand Tour win in only his second attempt.
Bernal is the third youngest winner of the Tour. The youngest is France's Henri Cornet, who was 19 when he was controversially awarded victory in the second edition of the race in 1904, while Luxembourg's Francois Faber was a few days younger than Bernal when he took the 1909 title.
Final general classification standings:
1. Egan Bernal (Col/Ineos) 82hrs 57mins 00secs
2. Geraint Thomas (GB/Ineos) +1min 11secs
3. Steven Kruijswijk (Ned/Jumbo-Visma) +1min 31secs
4. Emanuel Buchmann (Ger/Bora-Hansgrohe) +1min 56secs
5. Julian Alaphilippe (Fra/ Deceuninck-Quick Step) +3mins 45secs
6. Mikel Landa (Spa/Movistar) +4mins 23secs
7. Rigoberto Uran (Col/EF Education First) +5mins 15secs
8. Nairo Quintana (Col/Movistar) +5mins 30secs
9. Alejandro Valverde (Spa/Movistar) +6mins 12secs
10. Warren Barguil (Fra/Arkea-Samsic) +7mins 32secs
Stage 21 result:
1. Caleb Ewan (Aus/Lotto-Soudal)3hrs 04mins 08'secs
2. Dylan Groenewegen (Ned/Jumbo-Visma) Same time
3. Niccolo Bonifazio (Ita/Total Direct Energie)
4. Max Richeze (Arg/Deceuninck-Quick-Step)
5. Edvald Boasson Hagen (Nor/Dimension Data)
6. Andre Griepel (Ger/Arkea-Samsic)
7. Matteo Trentin (Ita/Mitchelton-Scott)
8. Jasper Stuyven (Bel/Trek-Segafredo)
9. Nikias Arndt (Ger/Sunweb)
10. Peter Sagan (Svk/Bora-hansgrohe)