The actor, writer and disability advocate was born with a bone disease called osteogenesis, commonly referred to as brittle bone disease.
He died from a suspected asthma attack.
Mr Kenihan was particularly well known for the television interviews he did throughout the years with journalist Mike Willesee. The first interview was conducted when Mr Kenihan was aged 7.
The series of interviews eventually turned into a documentary entitled Quentin. Many Australian TV viewers became familiar with Mr Kenihan's story through the interviews conducted by Willesee.
Viewer Contessa JenRed said his determination as a child inspired many.
He also played Corpus Colossus in Mad Max: Fury Road.
In 2016, he released an autobiography entitled Not All Superheroes Wear Capes, which he subsequently turned into a stand-up comedy performance show for the Adelaide Fringe Festival.
His trademark wit and humour was also on display in 2001 when he had his own TV show called Quentin Crashes.
Actor Russell Crowe said he is devastated at the news of Mr Kenihan's death, describing him as "the bravest bloke I ever met".
Other messages of condolence soon followed.
Former Olympian Nova Peris said Mr Kenihan was dearly loved.
Earlier this year in July, Mr Kenihan ran for a position on the Adelaide City Council at the upcoming November elections.
At the time, he told The Advertiser the decision was motivated by a sense of contributing to the community he so loved.
"I want to inspire people that anyone can have a say and help run their council — I know that seems lame and stereotypical, but it’s true," he told the paper.
"I’m at a point now that I’ve done everything that I’ve ever wanted to do.
"I’m here to make it (council) a bit more colourful. I just hope that constituents will trust me to take what they want into council so I can be their advocate."
In a live video on his YouTube account, dated 7 May, Mr Kenihan thanked his supporters, urging them to "live the best lives you can".
Australians continued to share stories of their interactions with Mr Kenihan and the impact he had on their lives.
"A relentless achiever," Jethro Heller posted on Twitter.
"Quentin Kenihan’s life was an extraordinary story of courage," South Australian opposition leader, Peter Malinauskas wrote.
Miles Kemp called for a state funeral to honour Mr Kenihan's achievements and contributions.
"One of the great South Australians. He was the embodiment of mind over matter," he said in his message on Twitter.
Howard Coombe posted his tribute message on YouTube, saying Mr Kenihan's death is a huge loss to the South Australian community and also to the Adelaide City council.
