Humphries - now the world number one - has added darts' ultimate prize to the World Grand Prix, Grand Slam of Darts and Players Championship Finals titles he's already picked up in the past few months.
Littler battled hard and led the match on more than one occasion, but was unable to cope with the experience and relentless 180-hitting power of Humphries.
Humphries threw a staggering 23 180s during the contest, averaging over 103.
Littler himself landed 13 180s with a very strong 101 average, but it was not enough to stop the might of his opponent.
Both players also threw out a spectacular array of ton-plus finishes, a 170 'big fish' each and back-to-back identical 108 checkouts.
After the game, Humphries told Sky Sports about his victory: "I cannot put this into words.
"I'm really proud of my performance, I am world champion and world number one. I really can't ask for more.
"I needed to win this one, as he (Littler) will win plenty of these."
"He has been an unbelievable talent, you will never see a more down-to-earth 16-year-old."
Littler, who has captured the attention of the world and brought legions of new fans to the sport during his stunning run to the final - was gracious in defeat.
"It has been unbelievable. The one negative was I lost too many legs with my throw so Luke could break me," the youngster told Sky Sports.
"That was the only negative, I just couldn't hold my own throw and I didn't win.
"Every game has been good but that one has just really annoyed me, especially the three missed to keep it going.
"That's what the crowd wanted but fair play to Luke, he deserves it."
Having entered the tournament for the first time ranked 164th in the world, Littler now moves up 31st in the rankings.
