Littler was tested immediately by James Wade, who stormed out of the blocks, racing to a 5-0 lead.
Wade, a World Matchplay champion before Littler could walk, displayed his trademark steel with a succession of clinical finishes, leaving Littler briefly adrift and muttering to himself at the back of the stage.
The Warrington teenager was not ready to throw in the towel.
Instead, he regrouped, rattling off five legs on the trot, chiselling the deficit to parity with a blend of nerveless finishing and relentless scoring.
By the time Littler levelled at 5-5, it was clear this was no coronation - it was a contest.
What followed was an exhibition in high-quality, high-pressure darts.
High scoring, high quality
Both players threw with three-dart averages north of 100, with Littler ultimately registering an extraordinary 107.24.
The Nuke peppered the treble 20 bed with 17 maximums, breaking the World Matchplay record and outgunning Wade, who was no slouch with six 180s of his own and an average of 101.54.
Both hovered around the 40 per cent mark on their doubles, keeping the quality unrelenting and the margin fine.
The pendulum then swung through the middle session. Littler produced a perfect storm of scoring and composure, at one point firing off back-to-back 180s to threaten a nine-darter, only for the eighth dart to drift agonisingly wide.
Each time Wade pressed, Littler countered, showing maturity that belied his age. When Wade clawed back to within a leg at 14-13, Littler simply raised his game, taking out an 80 in two darts and then hammering home a ruthless 115 checkout - treble 19, double 19 - to seal the title.
'I don't want to be 5-0 down again'
"I came here last year and lost in the first round, and some people thought I might have lost again," Littler told Sky Sports after the impressive victory.
"I am just so happy that I can pull myself out of these scorelines. But I don't want to be 5-0 down again.
"Since I started on the tour, I have always said to myself 'as long as I win one of every major, I will be happy'. I only have a few left to tick off.
"I'll now be chasing the majors I have not won yet. For now, we will have a week off and then see everyone in Australia."
For Wade, it was a night of familiar frustration, his 20th major final appearance ending in defeat despite periods of top-class darts and his ever-present game management.
By the close, Littler had amassed 17 180s, eclipsing even his own high standards and driving the match total into new territory for the tournament. His surge to the finish line, winning four consecutive legs, demonstrated the kind of sporting cruelty that marks out true champions.
Elite company
This was more than another televised triumph. By lifting the Phil Taylor Trophy and pocketing £200,000, Littler became only the fifth man to win the World Matchplay, Premier League and World Championship - and comfortably the youngest by some margin.
This triumph also extends Littler's record-breaking run through the week. In the semi-final against Josh Rock, he produced a televised nine-darter - already the fourth of his young career - when trailing 6-1, and the match total of 29 180s between them set a new World Matchplay record.
Littler contributed 15 of those maximums and averaged 107.5, turning the contest in dramatic fashion to win 17-14.
Earlier, in the quarter-final versus Andrew Gilding, Littler crushed a record with 18 180s and a 103 average, holding off a backlash to prevail 16-14.
His 64 tournament 180s also smashed the tournament's previous record of 56, held by Adrian Lewis.
He now sits within touching distance of Luke Humphries at the top of the PDC's World Order of Merit.