With two stunning vaults, including a spectacular version of her signature Yurchenko double pike, Biles improved to three-for-three in Paris after claiming the individual all-around title and team gold with the USA.
Biles was simply untouchable, leaving reigning Olympic and world champion Rebeca Andrade of Brazil delighted with silver as American Jade Carey took bronze.
Biles took control with her opening vault, the Yurchenko double pike now named the Biles II.
After a season spent perfecting the vault, Biles said she had performed it for the last time.
"I kind of nailed that one," Biles said.
On a vault so difficult no other woman attempts it, Biles soared off the vault table and even though her momentum carried her back a step on landing, her execution score of 9.4, along with the 6.4 difficulty score, added up to a score of 15.700.
Biles produced another explosive effort on her second vault, a Cheng, scoring 14.900 for a winning average of 15.300 points.
Andrade opened with a beautiful Cheng vault that garnered 15.100 points. She had a slight hop on the landing of her second vault for a 14.833 and an average of 14.966.
Carey was the last of eight finalists and snatched bronze with an average of 14.466, denying North Korea's An Chang-ok.
Biles, clad in shimmering red, gave a big smile as she received another rapturous reception at Bercy Arena.
Her smile was just as big as she saluted the judges after landing her second vault, and she was still smiling as she high-fived coach Laurent Landi.
The US great now owns a total of 40 world and Olympic medals -- 30 of them gold.
Biles, 27, is already fielding questions about Los Angeles 2028, to which her answer Saturday was "Never say never."
She still has plenty to do in Paris, with balance beam and floor exercise finals coming up on Monday, capping her return to the Olympic pinnacle after a bout of the disorientating and dangerous mental block called the "twisties" saw her pull out of most of her events in Tokyo.
Hailed by many for prioritizing her mental health, Biles was also criticized by some as a quitter three years ago.
As she burnishes an Olympic legacy launched with four golds in Rio, Biles has noticed the critics are oddly silent.
"They're really quiet now, so that's strange," she said with a laugh.
Biles's latest stunning turn was sandwiched between a pair of Olympic firsts.
Yulo won the men's floor exercise to give the Philippines a first gymnastics gold -- and just their second Olympic gold medal ever -- while McClenaghan triumphed on pommel horse to give Ireland a first Olympic gymnastics medal.
Yulo pulled out all the stops, upping his degree of difficulty mark from qualifying and nailing his gravity-defying three-and-a-half twist to close his routine for a score of 15.000 points.
"In the qualifications, I played it very safely," Yulo said. "Today, I felt I couldn't hold back and hesitate. If I really wanted to win, I needed to give my everything."
Yulo, 24, pushed Tokyo Olympic champion Artem Dolgopyat into second with a routine that garnered 14.966 points and Britain's Jake Jarman earned bronze with 14.933 points.
Yulo, whose career ups and downs have included vault and floor world titles but also a disappointing Tokyo Games campaign and a last-place finish in all-around qualifying at last year's world championships, collapsed in tears as the final competitor's score was read and he was confirmed as champion.
McClenaghan, a two-time world champion, edged out Kazakh Nariman Kurbanov on pommel horse.
American internet sensation Stephen Nedoroscik earned bronze as Britain's Max Whitlock was not only denied a third straight gold in the event but also in his bid for an unprecedented fourth straight medal on the same apparatus.
