The muscular Spaniard had won all 10 of his previous Roland Garros finals and although Thiem was the only man to have beaten him on clay over the past two seasons, the Austrian never threatened the claycourt master on Sunday.
"It's fantastic now, I can't describe my feelings", Nadal told the crowd on Philippe Chatrier Court moments after capturing his 17th Grand Slam trophy with a 6-4 6-3 6-2 victory.
The victory also allowed the 32-year-old Spaniard to hold onto the No. 1 ranking.
Nadal enjoyed a fast start to the encounter, winning the opening six points on his way to going 2-0 up in the first set.
Understandably, Thiem looked edgy as the match begun and he managed to win only one of the first eight points as Nadal, cheered loudly when he walked on court, bristled with intent. Key in that regard was his backhand, which consistently flustered Thiem, who didn't have the same bag of tricks at his disposal.
Rafael Nadal vs Dominic Thiem LIVE STREAM Dominic Thiem is chasing his maiden Grand Slam title
Nadal joins Australia's Margaret Court as the only player to win 11 titles at the same major.
The signs were already ominous for Thiem at that stage because in 112 best-of-five-set matches, Nadal had never lost after taking the first set.
Up a break at 2-1 in the third set, Nadal stopped serving after a fault because he couldn't straighten his left middle finger.
Nadal ended a three-year Grand Slam drought with a brilliant performance against Stan Wawrinka in the 2017 French Open final.
"And the strength that he has and the mentally, everything is ideal, works flawless for him playing in clay".
Thiem is playing at his limit just to stay in touch.
The top-seeded Nadal enters Sunday with a 10-0 record in title matches at Roland Garros and an overall career mark of 85-2 at the clay-court Grand Slam tournament. Nadal, Federer, Novak Djokovic and Andy Murray - the so-called Big Four - have dominated the men's game to such a degree that Thiem is only the second player now younger than 28 to have reached a major singles final.