The 18-year-old was born and raised in San Francisco. She attended high school in there, and has won a place to study at Stanford.
Her mother Yan is a first-generation Chinese immigrant and her father, reportedly American, has never been publicly named.
Despite competing as an American for most of her youth career in freestyle skiing, Gu will this year compete at the Olympics for China.
She made the decision in 2019 at the age of 15, claiming at the time she wanted to inspire a generation of young Chinese girls to pursue winter sports - which are comparatively less celebrated and glamorous in Asia than in the US.
It is unclear now where Gu's American citizenship stands - China does not recognize dual citizenship and minors under the age of 16 cannot renounce their US citizenship because they are not deemed mature enough to make the decision.
Gu's reps will not confirm whether or not she has given up her American citizenship, or if China has asked her to.
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Californian born skier Eileen Gu, one of the most promising young stars of the Winter Olympics, will compete for China at this year's games after turning her back on Team USA. She is pictured in January at the Toyota US Grand Prix Mammoth Mountain
Gu is pictured with her Chinese mother, Yan. She was born in San Francisco and grew up there. Her father, reportedly American, has never been named publicly
In 2019, at the age of 15, Gu announced plans to compete for China at the Olympics, and not the US. She said she wanted to inspire a generation of Chinese youngsters at the Beijing Games
After touching down in China last week, Gu delighted fans on Weibo - where she has 1.3million followers - with a picture with some dumplings
While choosing to represent China - where she is known as 'Gu Ailing', 'the snow princess' and has 1.3million on Weibo - she maintains significant sponsorship deals from American brands like Cadillac, Tiffany's, Visa, Therabody, Victoria's Secret, Oakley and Red Bull.
In interviews, she doesn't seem to recognize or discuss the huge conflict of representing one of America's longest-standing foes while still cashing in on her celebrity.
'When I'm in America, I'm American. When I'm in China, I'm Chinese,' Gu, who speaks fluent Mandarin, said in an interview with Red Bull's Bulletin recently.
When she touched down in Beijing last week, she went on Weibo to tell fans she'd just finished a plate of dumplings.
Gu's decision to abandon Team USA and compete for China