While Ariarne Titmus, Kaylee McKeown and Mollie O'Callaghan are the big names in Australia's powerhouse swimming squad, Jack's journey "through hell" to make the grade is compelling.
With the 2020 Tokyo Olympics in her sights, her world came crashing down after testing positive for the muscle growth agent ligandrol in an out-of-competition test in June 2019.
She was banned for four years despite proclaiming her innocence, insisting the substance entered her system by contamination. "I won't stop until I clear my name," she vowed.
Her case has similarities to the Chinese doping scandal that blew up in the sport this year.
In that instance, 23 Chinese swimmers tested positive for the prescription heart drug trimetazidine before the Tokyo Games, but they escaped suspension or sanction.
Instead, the World Anti-Doping Agency (WADA) accepted the explanation of Chinese authorities that the results were caused by food contamination. The case was revealed by the New York Times and German broadcaster ARD in April.
An independent report this month said that WADA had not shown "favouritism" towards China and the International Olympic Committee expressed its "full confidence" in the anti-doping body ahead of the Paris Games, which begin next week.
Jack is yet to address the issue and how it compares to her treatment, not wanting it to impact her Olympic preparations.
"To be honest, I've tried to put it on the back burner for now," the 25-year-old told reporters at the Australian trials in Brisbane of the Chinese scandal.
"But I'll definitely be commenting on it after the Olympics."
Ahead of the Covid-delayed Japan Olympics, the Lausanne-based Court of Arbitration for Sport concluded that "on the balance of probabilities" Jack "did not intentionally ingest ligandrol".
It reduced her ban to two years, but by then it was too late and she missed out on her childhood dream of becoming an Olympian.
Absolute despair
Jack told the Sydney Morning Herald her mental health deteriorated to the point that she started seeing a psychiatrist.
"I was going through hell at times. I felt alone," she said.
"I would have my partner, my dogs, my family, my friends, and they couldn't take away my pain."
She credited her coach Dean Boxall for helping pull her out of the fog and back into the pool.
"That man is the person who would answer my call at 2am when I was crying and didn't know what to do," she said.
"When I didn't have a reason to get up each day, he was the man who said: 'Shayna, get your ass off the couch and get to the pool. Go just get in the water. Remember why you swim. Remember why you love it'."
Jack eventually resumed training and, laser-focused, set about returning to the top, making Australia's 4x100m relay team for the 2023 world championships where they shattered their own world record.
Her speed has only improved since and she qualified for Paris alongside O'Callaghan for the 100m freestyle at the expense of defending Olympic champion Emma McKeon.
Jack also bagged one of two spots in the 50m freestyle with Meg Harris, shedding tears as the magnitude of her achievement sunk in and the crowd embraced her despite her chequered past.
"I think, for me, it's just using every bit of motivation from anybody who ever doubted me and knowing that I reached points of absolute despair and not even knowing if I wanted to return to the sport," she said poolside after making the team.
"It's just happiness. I'm just so proud of myself."
