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Donnacha O'Brien hails from Ireland's first family of Flat racing, the youngest son of the maestro Aidan O'Brien and brother to fellow trainer Joseph.
Born and reared in Ballydoyle, Donnacha O'Brien's life has intertwined with some of the greatest performers of this century and now he is forging his own way in the game as a trainer.
The youngest of four children born to Aidan and Anne-Marie O'Brien, Donnacha is immersed like his siblings in the family trade.
Like Joseph, Sarah and Anastasia before him, Donnacha spent time in the saddle. He enjoyed a brief but hugely successful career as a jockey, winning Classics in both Britain and Ireland. Height and weight were soon an issue and come late 2019, aged 21, he announced his plan to retire from race riding and move into the training ranks.
His first winning ride was on Quartz, trained by his father, at Dundalk in September 2014. He famously gained a maiden Group 1 success on Intricately in the 2016 Moyglare Stud Stakes, the horse bred by his mother and trained by Joseph.
The champion apprentice in 2016, he emulated Joseph by becoming Irish champion jockey in 2018 and, just like his brother, he would retain the crown a year later. Both of Donnacha's title wins featured 111 winners.
After turning pro, Donnacha O'Brien rode for his father's Ballydoyle operation, dealing with not just the pressure of working for his father, but doing so on board some of the most expensively acquired and prodigious thoroughbred talents in the world.
Although his Group 1 breakthrough came for Joseph, he would also win a second Moyglare Stud Stakes on board Happily in 2017 for his father in the famous silks of the Coolmore operation so renowned with Ballydoyle.
In Britain he twice won the 2000 Guineas at Newmarket on board Saxon Warrior (2018) and Magna Grecia (2019) for Aidan and the Coolmore posse. He won five UK Group 1s in a brilliant spell in 2018, including The Oaks at Epsom on Forever Together.
After calling time on his career in the saddle, Donnacha O'Brien quickly set about making his mark on the training ranks.
He started in January 2020 and had his first winner when the Gavin Ryan-ridden Flower Garland won the Irish Stallion Farms EBF Fillies Maiden at Dundalk a month later.
He became the youngest trainer from Ireland or Britain to win a Classic when the Pierre-Charles Boudot-ridden Fancy Blue landed the Prix de Diane (French Oaks) at Chantilly that summer, the handler aged just 21 years and 349 days.
The same filly won the Group 1 Qatar Nassau Stakes at Glorious Goodwood on her next start, the young trainer scoring with his first runner on UK soil, and an incredible start was sealed when Shale won the Moyglare Stud Stakes at the Curragh in September for his first Irish Group 1 as a trainer.
The filly Porta Fortuna went on to become a star for Donnacha, winning four Group 1s in Britain and Ireland including the Coronation Stakes at Royal Ascot in 2024.
The 2018 Irish Derby at the Curragh is a contest unlikely to be forgotten in the O'Brien household.
Aidan had the even-money favourite Saxon Warrior in the hands of Ryan Moore but they could manage only third, with Rostropovich (second), Delano Roosevelt (fourth) and The Pentagon (fifth) ensuring the Ballydoyle maestro had four of the first five finishers.
Nothing spectacular in that, but first past the post was Latrobe in the hands of his son Donnacha, trained by his other son, Joseph.
Despite missing out, Aidan O'Brien suggested post-race: "I can't tell you how delighted we are. I stopped giving them pocket money a long time ago!"
For Donnacha, it was a third British or Irish Classic of the year and the win more than helped silence any doubters who believed he was only getting big-race rides due to being his father's son.
