Jockey Stefano Cherchi has died aged 23 two weeks after being hurt in a fall.
The Sardinian, who previously rode in Britain, fell during a meeting at Canberra, Australia.
His girlfriend Brittany, daughter of legendary former jockey Kieren Fallon, had travelled to be at his bedside.
"With deep sadness, the Cherchi family have announced their beloved son Stefano passed away peacefully today," said the New South Wales Jockeys Association.
"The family are very grateful for the love, prayers and messages sent by the racing community across the world."
The rider was placed in intensive care with a serious head injury after his mount fell during a race at Canberra on 20 March.
Cherchi's horse Hasime came down in an incident that involved two other horses.
While the other two riders and all of the horses avoided injury, Cherchi was attended to by medics on the track for about an hour before being taken to hospital with a head injury and internal bleeding.
Cherchi, who had been an apprentice jockey with Newmarket trainer Marco Botti, rode more than 100 winners in Britain before relocating to Australia at the start of the year.
"Today is an absolutely heartbreaking day for us all but Stefano will always be with us. His charming character and smile can never be forgotten," said Botti.
"Our thoughts are with the Cherchi family and his close friends."
The British Horseracing Authority said the jockey was held in high esteem around the world.
"The entire racing industry will be in mourning after the loss of such a talented young man," it added.