But up until Sunday there was one jewel still missing from his already glistening crown -- and it wasn't one of the two majors he is yet to win.
The 22-year-old accomplished one of his lifelong ambitions by winning his first PGA Tour title in his home state of Texas.
The previous weekend he dropped from title contention at the Byron Nelson event in Irving to finish 18th after a closing 74, but he made no mistake at the Dean & Deluca Invitational despite being reminded all too vividly of one of his biggest career disappointments
by a heckler in the watching gallery.
"No matter what happens in the next 30 years of my career," Spieth told reporters after his final round at Colonial in Fort Worth, "this will be one of the most important days that I've ever had."
World No. 2 Spieth has now won eight PGA Tour titles before the age of 23 -- one more than Tiger Woods, but still behind Horton Smith's leading 14 -- but it wasn't all plain sailing in the Lone Star State.
The two-time major winner was level par for the day at the turn, before a shout of "remember the Masters" from somewhere in the crowd on the 10th stirred him to life, sinking a 20-foot putt for birdie.
"Either way," Spieth said when asked if it was a jibe or a gee-up, "there's a little red-ass
in me -- and it came out on the next few holes."
Two birdies followed to make it three in a row and move him into the lead -- and even a bogey on 13 wouldn't derail Spieth's charge.
He steadied himself with two consecutive pars, before a blistering finish of another three straight birdies gave him a three-shot victory over compatriot Harris English ahead of the season's second major event, the June 16-19 U.S. Open.
It was his second PGA Tour title this year, and the $1.2 million winner's purse took his season's prize money to $4 million from 12 tournaments and over $24 million since becoming a full member in 2013.
The red plaid jacket might not be the green of the Masters -- the scars of last month's capitulation at Augusta will continue to burn Spieth
-- but, for now, it's certainly a nice alternative.
"They both fit great," he said.
Meanwhile, Masters champion Danny Willett finished third at the European Tour's flagship event, the BMW PGA Championship
Willett was two shots behind fellow Englishman Chris Wood on Sunday, while 148th-ranked Swede Rikard Karlberg was a surprise runner-up.