The world number one pair took just 34 minutes to conquer third-ranked Nils Ehlers and Clemens Wickler, who were previously unbeaten before eventually denied the top accolade and will leave Paris with silver.
The sun set over a clear Paris sky as teams battled on the sand for the final day at the spectacular venue, where thousands of enthusiastic spectators have flocked over two weeks to snap selfies in front of the Eiffel Tower.
Ahman and Hellvig, both aged 22, looked like they were thoroughly enjoying themselves, spinning on the sand, high-fiving and being cheered on by fans dressed in bright yellow.
They kept the constant edge over the German pair to win the first set by an easy 21/10, and while Germany narrowed the gap in the second set it ended 21/13 after a dramatic fumble over the net at the end.
Ehlers, who stands at 6 feet 11 inches (2.11 metres), used his height to make some superb blocks but was met by strong returns from the youthful Swedes, and the Germans gave away several points by sending the ball long.
The Swedes applauded and bowed to the crowd after the match as the illuminated Eiffel Tower twinkled behind them.
The top-ranked Swedish pair have become famous for their style of attacking play called the "Swedish jump-set", which adds an element of unpredictability to attacking play.
Other players have admitted to trying to copy the style with varying degrees of success throughout the Paris Games.
Swedish fans dressed roared their approval as the final point was awarded, storming down the stands and singing along to "Mama Mia" by Swedish pop legends ABBA.
'Always fighting'
Tokyo 2020 gold medallists Anders Berntsen Mol and Christian Sandlie Soerum of Norway won the bronze medal, also marching to victory in two short, straight sets.
The Norwegian pair coolly triumphed over Cherif Younousse and Ahmed Tijan of Qatar, bronze medallists in Tokyo, in just over half an hour, winning 21/13, 21/16.
The Qataris had won fans in Paris for their style of play and interaction with the crowd, but they didn't find their groove on Saturday despite some brave play, including one valiant dive that left Younousse face down in the sand.
They rallied in the second set to deny the winning match point twice, but not enough to stop Norway claiming their win.
"There's a lot of people who want to be in our shoes right now," Bernsten Mol told reporters afterwards.
"And so, with this in the back of our heads, we're super proud but we're always fighting for gold."
For the women's final on Friday night, "I love Paris" had been drawn across the sand; for the men's final a large Eiffel Tower had been sketched across the court with acrobats and dancers entertaining crowds.
Beach volleyball has become one of the most popular events at the Olympics since its inclusion in 1996.
But the sport has drawn particular attention in Paris both for its spectacular location, and for the controversy surrounding Dutch player Steven van de Velde, a convicted rapist who was controversially selected for the Olympics despite his criminal past.
