Oskar "Oski" Rozenberg Hallberg now has double World Cup gold in skateboarding, the discipline park.
And became Sweden's first skateboard Olympian at the Olympics in Tokyo.
But the 25-year-old's life was in danger two weeks after he was born.
This is revealed by Oskar's mother Irena Rozenberg in the new SVT documentary "Oski - an Olympic skateboard saga".
- He breathed very hard, then we went to the children's clinic with him.
A doctor found that his heart was beating twice as many times a minute as it should.
We became very worried, we were transported in ascension to Lund and they put him there overnight.
In the morning, a chief physician came on tour, and he said that your son is seriously ill.
And then ... it's hard to talk about it ... he also said that if Oskar is not operated on immediately, he will die of heart failure, says Irena Rozenberg.
Mother Irene and father Johnny found out that Oskar had a 50 percent chance of surviving.
- The operation went well, they said that more operations will be needed, but not a single one was needed.
The doctor told us that most "heart babies" work.
They may be a little leaner, they may be less energetic - but they can live completely ordinary lives.
The only thing they could say for sure was that he will not be able to do is become an elite athlete.
Watch "Oski - an Olympic skateboard saga" on SVT Play.