The 41-year-old Swiss, a three-time Grand Slam winner, is retiring at the end of the season. He made his final Roland Garros appearance 21 years after his first.
De Jong sealed the victory with a whipped forehand winner, then urged the fans to applaud Wawrinka, whose face was almost as red as the baking-hot clay as temperatures soared.
"It's hard, it's hard to say goodbye to you here," an emotional Wawrinka said. "It's because of Roland Garros that I wanted to become a tennis player."
The veteran player was given an ovation at Court Simonne-Mathieu, where he got fans to do a Mexican wave before leaving. He had been scheduled to face Arthur Fils but the rising French star pulled out of the tournament with a hip issue.
Wawrinka got the crowd going, at times asking for more encouragement with a broad grin on his face. He applauded the spectators back, tapping his racket after winning a point. One fan held up a sign with 'Stan the Man' written on it, another with 'Stan still the Man'.
He knows it will be hard to let go, although he still has Wimbledon and the US Open to come.
"For more than 20 years I experienced these emotions, you never want it to stop," Wawrinka said. "I have given everything for this sport."
His stunning 2015 run to the title saw him defeat heavy favourite Novak Djokovic in the final after downing another all-time great, Roger Federer, in the quarter-finals.
Wawrinka stood out that year as much for his eye-catching pink-checkered shorts as for his destructive backhand.
Those shorts fed his happy-go-lucky appearance and he reinforced that image by celebrating with champagne long into the night. But as cavalier as he sometimes seemed, Wawrinka was anything but casual and always trained fiercely hard.
Elsewhere, last year's quarter-finalist and 19th seed Frances Tiafoe beat fellow American Eliot Spizzirri 6-3 7-6 (7-5) 6-4 6-3.
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