After a hard fought first set, the number one seeded Nadal dominated the rest of the match to capture his 17th grand slam title.
It is Nadal's 11th singles title at Roland Garros, five more than any other man in the Open Era.
"It's incredible 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 Spaniard now inches closer to Roger Federer's all-time record of 20 Grand Slam titles.
Although Thiem stood tall and broke Nadal early in the opening frame, he fell apart with a chance to knot things at five games apiece and ceded the set to Nadal at love.
Nadal's win-loss record at the French Open, his only two losses coming against Swede Robin Soderling in the fourth round in 2009 and against Djokovic in the quarterfinals in 2015.
"I am sure you will win here in the next couple of years", Nadal told Thiem afterward.
He followed that up with his second title at Wimbledon with a straight-sets victory over Czech Tomas Berdych.
Rafael Nadal and historic firsts at Roland Garros are inseparable.
INFINITE With Surprise Trailer at E3 — Microsoft Reveals HALO
The last time we saw a proper game in the Halo series was with the fifth game, Guardians , about three years ago. We know it'll be developed by 343 Industries, and it'll apparently use a new engine called "Slipspace".
Thiem's fighting spirit was evident in abundance - he continued to put pressure on Nadal through his return game, while consistently scrapping to stave off perilous positions on his own serve - but ultimately the Spaniard's quality and, often, his sheer force of will, won the day.
Here are the list of numbers behind Rafael Nadal's 11th French Open crown.
Despite matching Nadal forehand for forehand, Thiem was undone in the 10th game when three errors handed Nadal the opening set after 52 minutes on court.
But Thiem showed resilience in getting two break points on Nadal's serve.
He also let four match points go at 5-2 but he would not be denied as Thiem went long with a backhand.
Another feature was his ridiculously slow play when serving, nearly always over the 25-second limit and sometimes going well into the thirties. Further proof: He has lost only one set in the past two years at Roland Garros.
If there were any reason for a bit of intrigue entering Sunday's match, it was this: Thiem beat Nadal in two sets on red clay at Rome in May 2017 and again at Madrid last month.
Even though Nadal is the overwhelming favourite in the summit clash, the seventh seeded Dominic Thiem is no slouch on clay either.
The women's doubles final is also Sunday.