In a tense and physical grand final, the Panthers ran in three tries and their powerful defence limited the Storm to just one.
Only two other teams in the 117-year history of the competition had achieved the feat, with the last being when legendary St George reeled off 11 straight titles from 1956-66.
"No one's going to do this again (win four in a row)," Panthers star Jarome Luai said.
"To win one grand final is so special. I can't put this into words."
The Storm led for most of the first-half, but ran out of gas and were unable to replicate their stirring efforts from the 2020 grand final when they famously beat the Panthers.
"They are the best, so hard to beat and you have to be on top of your game for the full 80 minutes," Storm half-back Jahrome Hughes said.
After finishing two games clear at the end of the regular season, including a 2-0 record against the Panthers, the Storm entered the grand final as slight favourites.
The early exchanges were dominated by dogged defence until the stalemate was broken in the 22nd minute when Storm captain Harry Grant burrowed over the line.
But the Panthers hit back quickly through a try from Sunia Turuva that was superbly instigated by star half-back Nathan Cleary, who took his place despite battling a shoulder injury.
Cleary was again involved when he sent Liam Martin over the line as Panthers entered half-time with a 10-6 lead.
A tiring Storm side faced a daunting task against the Panthers, who had not lost a finals match after leading at the interval for 20 years.
Paul Alamoti gave the Panthers a stranglehold when he crossed over in the right corner in the 60th minute and their defence held firm to clinch a sixth title.
Earlier, Sydney Roosters survived a furious rally from Cronulla Sharks to claim the NRL Women's title after a thrilling 32-28 victory.
The Roosters led 24-0 at half-time before the grand final came alive when the Sharks scored four straight ties.
But a try from Olivia Kernick in the dying minutes sealed the Roosters' second title.
