Rose put together rock-solid rounds of 71, 72, 67 and 69 to finish level with Garcia on nine under par and the Englishman was delighted for his opponent to land his first major title at the 74th attempt.
Rose was an afterthought, five shots behind, when his tee shot to a left pin on the par-3 12th dropped in 5 feet from the hole for the first of five birdies on the back nine.
On a picture-perfect Sunday, on what would have been the 60th birthday of his countryman and idol, Seve Ballesteros, the 37-year-old Spaniard made a birdie putt on the first hole of a playoff to beat Justin Rose.
"Sergio and I have played a lot of golf together since we were 14 years old", said Rose, 36, who has been a team mate with Garcia on four European Ryder Cup teams.
Rose took the lead with an 8-foot birdie on the 16th and gave it back by missing a 7-foot par putt on the 18th.
The Sergio who dons the green jacket showed a tenacity matching the Spanish bull head cover for his driver. He turned with his arms to his side, blew a kiss to the crowd and then crouched again and slammed his fist into the turf of the green.
As Rose bogeyed the fifth hole, Garcia expanded his lead with a par.
He missed this one, too, and headed into a playoff against Rose, only this time he didn't lose hope. Rose ended up bogeying the hole, while Garcia notched a birdie. Instead, Spieth opened with bogeys on two of his first three holes. I'd like to win three or four Green Jackets, but one would be enough, you know. Rose birdied the hole, and the two golfers were all square with just three to go. The Spaniard had consecutive bogeys at 10 and 11, and his errant drive at the par-5 13th forced him to take a one-stroke penalty, putting Rose in position to build a commanding lead. "I felt the calmest I've ever felt on a major Sunday". But Garcia hung around to come back to tie Rose for the lead with an incredible eagle on No. 15.More news: North Korea says Syria airstrikes prove its nukes justified
Garcia did likewise when leaving the 13th green and trailing by two shots with just five to play. He chipped out under the tree, hit his third shot to 15 feet and missed the par putt.
Rose, victor at the US Open in 2013, and at the Rio Olympics last summer, took the lead with a birdie in the 16th, but he committed a bug in the 17th. He hit 80 percent of fairways (45-of-56), second most in the field (Soren Kjeldsen had 82 percent) along with 75 percent of his greens in regulation, tied for the second most in the field with Justin Rose (only Paul Casey had more at 78 percent). I kind of felt that if I could make that one - certainly his putt got very hard.
Charl Schwartzel closed with his second straight 68 to finish third at 6 under, one shot ahead of Matt Kuchar (KOO'-chur) and second-round co-leader Thomas Pieters.
And Rickie Fowler, who will "be all up for it tomorrow".
That why his comments all week at the Masters that he had changed his attitude, that he was learning to accept bad bounces, was met with skepticism.
Fowler had a memorable 2014 major season, finishing in the top five of all four events although he did not win.
"It's a coin flip, is it going to jump or come out spinny", Spieth said.
"But", he said finally, a wide smile stuck in place, "it's happened".