The top-seeded Italian secured his fourth Grand Slam title in three hours and six minutes with 40 winners, 40 unforced errors and eight aces.
He made history with his first slam on grass, becoming the first Italian man ever to win the singles title, going one better than Matteo Berrettini, who made the final five years ago.
Sinner signalled his intent early on, breaking Alcaraz in the fifth game of the opening set, but the Spaniard quickly restored parity with some brutal hitting from the back of the court.
The speed of Alcaraz's response looked to have rocked Sinner, and the Italian duly buckled under pressure as Alcaraz clinched the first set courtesy of a stunning cross-court winner on the stretch.
Undeterred, the world number one demonstrated his fighting spirit at the start of the second, surging into a 2-0 lead before holding firm on serve with some incredible shotmaking to take the set 6-4 and level the contest.
Sinner continued to threaten with his pinpoint return game early in the third, but Alcaraz found some clutch serves at 15-40 down to fend off the Italian.
Nevertheless, Sinner remained the more consistent of the two players throughout the set and finally broke through in the ninth game to deservedly move ahead in the match.
The one-way traffic showed no signs of slowing down, as Sinner pounced once again on Alcaraz's faltering serve. The Spaniard looked like he was getting himself back in the fourth set with two break points in the eighth game, but Sinner, who faltered when the pair met at the French Open final just five weeks ago as it looked won, found the resolve to win at a pivotal juncture.
It made Alcaraz serve to stay in the final, which he did with a sublime touch at the net, but Sinner made history with his second match point.
Speaking during the presentation following his historic win, Sinner started by saying: "I would like to start with Carlos. An amazing tournament, but mostly thank you for the player you are," Sinner said.
"It's so difficult to play against you, but we have an amazing relationship off the court and on the court ... keep going, keep pushing."
The world number one admitted that winning the title: "sounds amazing, I hope my career is a little bit longer and after I can come back here. It is amazing to be in this position.
"We were talking before the match that we would never thought we would be in this position when I was young. This was only a dream, the dream of the dream because it was so far away from where I'm from. I'm just living my dream."
He added, "I would like to thank my team and everyone who came here for this special day. It means so much. They keep pushing me to become a better tennis player, but also a better person. Thank you."
Even though it wasn't his day, Alcaraz admitted: "I'm just really happy and really proud about everything I'm doing."
"At the beginning of the season, I struggled a little bit on the court, but then suddenly I started to bring joy on the court again and that excitement I have every time I step on the court.
"It's a great journey so far, which I'm really proud of."
