Because of wet conditions, race organizers stopped the clock as Armstrong and the main pack entered Paris. Although riders were still racing, with eight laps of the Champs-Elysees to complete, organizers said that Armstrong had officially won.
The stage started as it has done for the past six years, with Armstrong celebrating and wearing the race leader's yellow jersey.
One hand on his handlebars, the other holding a flute of champagne, Armstrong toasted his teammates as he pedaled into Paris to collect his crown. He held up seven fingers, one for each win, and a piece of paper with the number 7 on it.
His sixth win last year already set a record, putting Armstrong ahead of four other riders, Frenchmen Jacques Anquetil and Bernard Hinault, Belgian Eddy Merckx and Spaniard Miguel Indurain, who all won five Tours.
Armstrong's new record of seven wins confirmed him as one of the greatest cyclists ever, and capped a career where he came back from cancer to dominate cycling's most prestigious and taxing race.
But Armstrong's last ride as a professional, the closing 89.8-mile 21st stage into Paris from Corbeil-Essonnes south of the capital, was not without incident.
Three of his teammates slipped and crashed on the rain-slicked pavement coming around a bend just before they crossed the River Seine. Armstrong, right behind them, braked and skidded into the fallen riders.
Armstrong used his right foot to steady himself, and was able to stay on the bike.
His teammates, wearing special shirts with a band of yellow on right shoulder, recovered and led him up the Champs-Elysees at the front of the pack.
Organizers then announced that they had stopped the clock because of the slippery conditions with more than 10 miles to go.
In retiring, the 33-year-old will manage a rare feat in sports--going out on the top of his game. Armstrong has said that his decision was final and that he was walking away with "absolutely no regrets."
His departure begins a new era for the 102-year-old Tour, with no clear successor. Armstrong's riding and his inspiring defeat of cancer attracted new fans, especially in the United States, to the race.
Millions turned out each year, cheering, picnicking and sipping wine by the side of the road, to watch him flash past in the race leader's yellow jersey, the famed "maillot jaune."