The No1 seed beat the American 6-1, 6-3 in Saturday’s final to secure her second title at Roland Garros.
With superstar Poland striker Robert Lewandowski watching on Court Philippe Chatrier, Swiatek’s sharp-shooting and ruthless finishing was too much for the American and capped an astonishing winning run.
Elevated to world number one following Ashleigh Barty’s shock retirement in March, the 21-year-old Pole has proved an unstoppable force ever since.
Her 35-match winning streak takes her level with Venus Williams for the most consecutive victories this century.
She has also won six straight titles, the first woman to do so since Justine Henin in 2008.
It was a tough afternoon for Gauff, in her first grand slam final, but she did not help herself despite saying beforehand that there was no pressure on her.
The teenager, who burst onto the scene at Wimbledon three years ago, made a nervous start with a double fault in her opening game helping Swiatek to an immediate break.
Gauff saved four break points in her next service game but succumbed to a fifth with a wild forehand, which was becoming a feature of the match already.
Swiatek was beginning to be tested, though, as Gauff finally got on the board with a service hold, but the top seed’s fist pump was on show for the first time when a forehand clipped the corner to move her 5-1 ahead.
And when yet another Gauff forehand drifted wide, Swiatek had wrapped up the opening set in only 32 minutes.
But Gauff clearly felt she was still in the match and cleverly fashioned two break points at the start of the second set, Swiatek duly obliging with a wayward forehand of her own.
However, rinse and repeat, another double fault and a loose forehand brought Swiatek back on serve and the next break soon followed.
Gauff bravely held for 5-3, but with dark clouds gathering in the Parisian skies and thunder in the distance, storm Swiatek blew her opponent away.
After receiving the Suzanne-Lenglen cup, Swiatek said: “First I want to congratulate you (Gauff) because you are doing an amazing job.
“You are progressing all the time. You will find it and you will be there, I am pretty sure of that.
“I want to thank my team, you guys, I mean, oh my god, without you I wouldn’t be here, I’m sure of that. I’m glad every piece has come together and we can do this. We deserve to be here. Thanks for your full support all the time no matter what.
“Also to my Dad, I wouldn’t be here without him, so I have to thank him for everything. Everyone who is in my box, thank you all.”
A tearful Gauff reflected on a chastening first experience of a major final.
“Congratulations Iga, what you have done these past few months has been amazing,” she said.
“Hopefully we can play many finals and I can get a win on you one of these days.
“I’d like to thank my team. I’m sorry I wasn’t able to get this one today.”
Additional reporting by PA.