The 30-year-old Landis cruised to victory on the Champs-Elysee, a day after regaining the leader's yellow jersey and building an insurmountable lead in the final time trial.
Landis picked up where another American left off just last year, when Lance Armstrong completed his seventh and final Tour triumph. Including three wins by Greg Lemond (1986, 1989, 1990), Americans have won the race 11 of the last 21 times.
Norway's Thor Hushovd, who also won the Tour prologue on July 1, won the final stage in a sprint ahead of the main pack, which included Landis and his closest rivals.
Rounding out the podium was Spain's Oscar Pereiro in second and Germany's Andreas Kloeden in third.
Assured of victory, Landis hoisted a champagne glass handed to him from the Phonak team car early along the 96-mile route from Sceaux-Antony to the capital.
Saturday, Landis placed third in the Tour's last time trial, wresting the yellow jersey from former teammate Pereiro and securing a 59-second lead over the Spaniard, who finished fourth in the stage.
That time deficit was a virtually impossible margin to overcome in the flat, short final stage because Landis and his team watched the Spaniard closely to make sure he didn't try to break away.
Landis, a former mountain biker who toiled for three years as a U.S. Postal Service team support rider for Armstrong, had sought to apply the Texan's conservative meticulous strategy for winning.
But "disaster" struck Wednesday in Stage 16 in the Alps.
Landis allowed Pereiro to take the yellow jersey as the race left the Pyrenees at the end of the second week to conserve energy for the three crucial stages in the Alps. That strategy seemed to backfire after Landis lost the jersey in a second Alpine stage at La Toussuire, dropping from first to 11th — 8 minutes, 8 seconds behind Pereiro.
Only with a stunning stage win Thursday in the final Alpine stage did Landis erase all but 30 seconds of that time deficit — putting him in a prime position to win by outpacing the Spanish rider in the final time trial Saturday.
For Sunday' finish, Russia's Viatceslav Ekimov, 40, led the peloton, the main rider pack, as it arrived for the first of eight laps on the famed Paris avenue to honor him as the Tour's oldest rider. It was the Discovery Channel rider's 15th Tour — one shy of Dutch cyclist Joop Zoetemelk's record.
Australia's Robbie McEwen won the green jersey given to the best sprinter for a third time, and Denmark's Mickael Rasmussen earned the polka-dot jersey awarded to the best climber for a second year. Italy's Damiano Cunego, 25, won the white jersey as the best young rider.