It took the Northern Irishman 11 goes, but finally he'd done it.
A Masters win, after a Sunday of perhaps unrivalled back-nine Augusta National drama, cemented the first men's golf career grand slam since Tiger Woods completed the set of all four majors titles in 2000.
McIlroy, the first European in what's now a six-man club, now has 29 PGA Tour titles and at age 35 is suddenly free of burden and needing just two more to enter the top-10 for all-time major wins.
The 35-year-old was 24 when he won his fourth and previous-last major and was only 21 when he let a four-shot lead on the back nine slip at Augusta.
Having led by the same margin, he rose from the canvas after a shattering fourth double bogey of the tournament - a record for any winner - at the 13th to see off the charging Justin Rose in a playoff.
McIlroy had blinked at last year's US Open and watched Cameron Smith fly by at the 2022 British Open, just two of many majors near-misses since his last title in 2014.
The Northern Irishman (11 under, 72, 66, 66, 73) was four shots clear through 10 holes but, as he did 14 years ago at Augusta National, stumbled with five dropped shots as Rose (65, 71, 75, 66) surged to finish level.
Brilliant approaches to the 15th and 17th gained him strokes and McIlroy was on the fairway on the 18th only needing a par to join a club that only included Woods, Gene Sarazen, Ben Hogan, Gary Player and Jack Nicklaus.
His wedge found sand and the par putt missed, McIlroy then nailing his approach to within four feet minutes and making the putt on the first playoff hole to end a day of theatre with tears of joy and consign English veteran Rose to a third runner-up placing.
Consecutive rounds of 66, including the best-ever start to a round on Saturday, helped offset a first-round 72 and put him alongside Nick Faldo and Woods in overcoming a seven-shot deficit after 18 holes to win.
"I'd like to start this press conference with a question myself. What are we all going to talk about next year?," McIlroy posed to journalists after more than a decade of enduring the career slam narrative.
"I have dreamt about that moment for as long as I can remember.
"There were points in my career where I didn't know if I would have this nice garment over my shoulders, but I didn't make it easy today.
"I've carried that burden since August, 2014.
"What came out of me on the last green there in the playoff was at least 11 years, if not 14 years of pent-up emotion."
Steady Australian Jason Day dropped shots on the last two holes to finish five under and in a tie for eighth.
But his total of five bogeys for the tournament was the least of all players by three.
Rose fell just short of executing the second-biggest Masters comeback after starting the final day seven shots behind.
The former world No.1, US Open and Olympic champion, joins Greg Norman as a three-time Masters runner-up and Ben Hogan as the only loser of multiple playoffs after his 2017 defeat to Sergio Garcia.
Min Woo Lee, Australia's only other cut survivor, was two over on Sunday to finish six over for the tournament in 49th.
CAREER GOLF GRAND SLAMS (when they won each for the first time)
* Gene Sarazen - US Open (1922), PGA Championship (1922), The Open Championship (1932), Masters (1935)
* Ben Hogan - PGA Championship (1946), US Open (1948), Masters (1951), The Open Championship (1953)
* Gary Player - The Open Championship (1959), Masters (1961), PGA Championship (1962), US Open (1965)
* Jack Nicklaus - US Open (1962), Masters (1963), PGA Championship (1963), The Open Championship (1966)
* Tiger Woods - Masters (1997), PGA Championship (1999), US Open (2000), Open Championship (2000)
* Rory McIlroy - US Open (2011), PGA Championship (2012), The Open Championship (2014), Masters (2025)
16°C