The Bucks lost the first two of their best-of-seven series but took the next four games to seal the title in front of their own fans on Tuesday.
Two-time MVP Antetokounmpo scored 50 points and posted 14 rebounds to lead the Bucks to their second championship, following their victory in 1971.
The achievement saw the Greek 26-year-old, who was named Finals MVP, become just the seventh player to score 50 points in an NBA finals game.
Antetokounmpo also had five crucial blocks in the game played in front of 17,000 fans at Fiserv Forum, while Chris Paul top scored for the Suns with 26 points.
The Bucks needed every one of their star forward’s points after the Suns came back from an early deficit to lead 49-42 at halftime.
Antetokounmpo went hard in the second half, scoring 32 points and going 16-for-17 from the foul line as he continually charged at the rim en route to victory.
He was ably supported by Khris Middleton, who came up with multiple clutch buckets down the stretch to keep the Suns at bay.
Phoenix, meanwhile, were left to rue some poor three-point shooting, which had been their bread-and-butter for most of the season.
The team shot just 6 from 25 from the deep with Devin Booker who finished with 19 points, missing all seven of his attempts from beyond the arc.