The diminutive dynamo dazzled at the 2016 Rio de Janeiro Games, winning gold in all-around, vault, floor exercise and team events.
She arrived at the pandemic-delayed Tokyo Olympics with superstar billing and history in her sights, but withdrew from the majority of her events as she struggled with the disorienting and "petrifying" mental block that gymnasts call the "twisties".
Hailed by many as a mental health trailblazer but criticized by a few as a quitter, Biles has returned from a two-year hiatus, at the age of 27, as good as or even better than ever.
In 2023 she took her tally of world and Olympic medals to 37 -- a cache she started with her first all-around world title in 2013, when she was just 16.
Now the owner of a record six world all-around crowns, Biles remains a must-see sensation even among such superstars as NBA legend LeBron James and pop diva Taylor Swift.
More than seven million Instagram followers basked in the fairytale photos of Biles's wedding to NFL player Jonathan Owens, who has received special dispensation from the Chicago Bears to miss a few days of training camp to watch her in Paris.
Swift took a moment during her Eras tour in Europe to tweet her approval when Biles chose a phrase from Swift's "...Ready For It" to kick off her floor routine at the US Olympic trials.
But Biles's ascent has featured as many twists as one of her signature tumbling moves.
Tokyo capped a tumultuous period that included Biles's revelation, in 2018, that she was among the hundreds of gymnasts who were sexually abused by former Olympic team doctor Larry Nassar.
She was a vocal critic of USA Gymnastics and the United States Olympic and Paralympic Committee over their handling of the scandal and a leading voice calling for their accountability after Nassar was convicted and imprisoned.
Biles, who will be the oldest woman gymnast to compete for the US since Marie Margaret Hoesly in 1952, had to laugh when she was reminded that she poked fun at a 22-year-old Aly Raisman as the "grandma" of the 2016 US team.
'Always running'
"I definitely have to apologize to Aly for calling her grandma because, whew, I feel like I'm way older now," said Biles, noting that nowadays her body feels it after a big competition.
"Back in Rio, I could do anything," Biles said. "I'd never needed tape, nothing. I was just like a little hamster on a wheel, always running."
Biles also pays meticulous attention to her mental health, "religiously" continuing the weekly therapy sessions she says are key to her successful return.
Olympics broadcaster NBC calculated that one tumbling pass in her trials floor routine saw her soar 12 feet above the mat.
She's made the Yurchenko double pike vault -- a vault so difficult no other woman has attempted it in competition -- a staple and it's now the fifth skill to be named for her.
"I think we always knew she could be better," says coach Cecile Landi, who with husband and co-coach Laurent Landi has shepherded Biles through her return.
"She's the most talented athlete I've ever worked with and so we just knew if she could get her mental game as well as her physical game, then she would be close to unstoppable."
Biles's path has been made easier by the supportive environment at World Champions Centre, the Texas gym owned and operated by Biles's parents, Nellie and Ron.
The couple, in actuality Biles's grandparents, adopted Biles and her sister Adria after they ended up in foster care, their biological mother unable to care for them amid substance abuse struggles.
Biles is joined on the US Olympic team by WCC buddy and Tokyo Olympic teammate Jordan Chiles.
Tokyo Olympic all-around gold medalist Suni Lee and floor gold medallist Jade Carey and 16-year-old newcomer Hezly Rivera round out the squad.
Biles, who was honored with the Presidential Medal of Freedom in 2022, knows that she and her teammates will still face haters who "want to see us fail".
But she's glad to be back on her own terms.
"Nobody's forcing me to do it," Biles said. "I wake up every day and choose to grind in the gym and come out here and perform for myself.
"Just to remind myself that I can still do it -- that's my why."
