The son of serial Irish Irish champion trainer Aidan O’Brien had a short but hugely successful career as a jockey before quitting because of recurring weight issues.
At 22, he instantly turned to training and just four months into his fledgling career scooped his first Group 1 via Fancy Blue’s tenacious win in the French Oaks.
The same filly landed the Qatar Nassau Stakes at Goodwood on her next start. It was Donnacha’s first runner in the UK.
He would end his first year as a trainer in Ireland with 17 winners from 107 runners.
As a jockey, he won the QIPCO 2000 Guineas in successive years aboard Saxon Warrior (2018) and Magna Grecia (2019) plus the Investec Oaks on Forever Together in 2018.
And Kew Gardens (Long Distance Cup) and Magical (QIPCO Champion Stakes) gave him a glittering Champions Day double in 2019 just five weeks before he quit the saddle.
His brother, Joseph, also enjoyed great success as a rider and is also excelling in the training ranks.