In a drama-filled grand final that included a biting allegation and bunker controversy, Penrith pulled away late in front of a crowd of 80,156 people at Accor Stadium on Sunday night.
The win makes them only the third team in history to claim four straight premierships, and the first since the great St George side won 11 in a row from 1956 to 1966.
It came as the result threatened to be overshadowed late by claims Melbourne star Cameron Munster had bitten Paul Alamoti's arm in the second half.
Munster denied the claim, but was put on report by referee Ashley Klein, who said he could not be certain what had happened.
Still, the story from the night was Penrith's fourth straight title.
Second-rower Liam Martin played close to the best game of his career for Penrith, claiming his maiden Clive Churchill Medal for player of the match.
Nathan Cleary was superb again despite appearing to struggle with his shoulder injury late on, while Brian To'o was powerful in yardage before suffering a knee injury.
Liam Martin dives over for one of the Panthers' three tries on the night. (Mark Evans/AAP PHOTOS)
Jarome Luai also had a fitting final ride in the Penrith No.6 jersey, playing a hand in the lead up to two tries in his last game before departing for Wests Tigers.
Melbourne desperately missed the suspended Nelson Asofa-Solomona in the middle, while their all-star spine lacked chances with Penrith's territorial dominance.
But they will also feel unlucky after a crucial bunker call in the 50th minute, when Jack Howarth appeared to go over and make it 10-10 with a kick to come.
Klein initially ruled that Dylan Edwards and Izack Tago had held Howarth up, before the bunker backed the call despite replays appearing to show the ball was grounded.
The 10-6 scoreline remained for another 10 minutes, before Martin gave Penrith a crucial eight-point advantage.
Chasing through on a Cleary bomb, he leapt to challenge Xavier Coates for the ball, claimed possession, then gave the ball off for Moses Leota to put Alamoti over.
Paul Alamoti's try settled the grand final at Accor Stadium. (Dan Himbrechts/AAP PHOTOS)
The Panthers then repelled five straight sets from the Storm on their own line, in what proved to be decisive plays on their way to another grand final win.
"No-one is going to do this again," a triumphant Luai said after the siren.
"I can't put it into words. History doesn't matter. We are soaking up this moment.
"Just to win one grand final is so special. This group of guys, no-one works harder than these boys and we got what we deserved."
Luai was also crucial in the win.
After Melbourne scored first through Harry Grant out of dummy-half in the 23rd minute, it was virtually all Penrith from that point.
The Panthers hit back almost immediately through a superb play on their left edge, when Alamoti passed the ball back for Luai to send Sunia Turuva over.
And with Penrith behind 6-4 just before the break, Luai stood up again to be involved in the game's most crucial play.
After a surging To'o run put Penrith on the attack, Luai changed the point of attack on the last tackle when he flung the ball right to Cleary.
Cleary then hit Martin with a short ball, allowing the edge forward to hit a hole and give the Panthers their 10-6 advantage at the break.
In charging on to victory, Penrith avenged their 2020 grand-final defeat to Melbourne and became the first fully professional men's team to win four straight titles in any Australian code this century.
"I'm actually lost for words," Cleary said.
"Four years ago I was standing there crying and losing to these guys who have been the best for such a long time.
"We've just won four in a row. It is honestly mind blowing."
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