Joseph's grandfather Joe Crowley was the first to train from the yard on Owning Hill and enjoyed great success there. In later years, Joseph’s parents Annemarie and Aidan were both crowned Irish Champion National Hunt Trainers while based there and Annemarie's sister Frances also trained an abundance of winners from the yard. Quite literally thousands of winners have been trained on its famous uphill gallop over the decades. With there having been substantial improvements and developments made to the yard in recent years, it is now very much a world-class training facility.
Joseph first came to worldwide prominence as a Flat jockey. While his career in the saddle only lasted six-and-a-half years due to the unwinnable battle he fought to keep the weight of his near six-foot frame below nine stone, no rider in the history of the sport has achieved more in such a short career.
Joseph rode his first winner less than a week after turning 16 on Johann Zoffany, trained by his father Aidan, at Leopardstown on May 28th 2009. Despite essentially only riding part-time as he was still attending school, O’Brien was involved in a three-way dead-heat for the title of Champion Apprentice in Ireland in 2010. He claimed that title for himself by a wide margin in 2011 and that was also the year he rode his first Classic winner with Roderic O'Connor winning the Irish 2,000 Guineas at the Curragh. Later that year he became the youngest-ever jockey to ride a Breeders’ Cup winner when partnering St Nicholas Abbey to success in the Breeders’ Cup Turf.
As his career progressed, the records continued to fall. In 2012, Aidan and Joseph became the first father-son trainer-jockey combination to win the Derby courtesy of the victory of Camelot and later that year Joseph was crowned Irish Champion Jockey with 87 winners. In October 2013, Joseph broke a 20-year-old record with a treble at Navan securing his 117th winner of the season, beating the previous record set by Mick Kinane. He finished the 2013 season with 126 winners and retained his Irish Champion Jockey title.
For all those records, Joseph’s lasting legacy in the saddle will be his Group 1 wins, with him riding 31 such winners all over the world during his short career. The highlights were the Derby (twice), the St Leger, the 2000 Guineas, the Irish Derby (twice), the Breeders' Cup Turf, the Grand Prix de Paris, the Dubai Sheema Classic and three consecutive renewals of the Irish 2,000 Guineas.
It was at the end of the 2015 season that it became apparent that Joseph was not going to be able to maintain the extreme lifestyle he had to lead in order to make the weight required to ride on the Flat. His retirement was confirmed in the spring of 2016, but the next chapter of his racing life had already commenced, as he had been combining his riding with training a string of horses from Carriganóg Racing on Owning Hill for a number of years. Indeed, Joseph was responsible for the training of Ivanovich Gorbatov when that horse won the Triumph Hurdle at the Cheltenham Festival under Aidan’s name in 2016.
Joseph was officially granted his license to train in June 2016 and made a quite remarkable start, saddling four winners on his first day with runners, including horses ridden by his siblings Donnacha and Sarah. His dream start continued when just a few months later he saddled his first Group 1 winner courtesy of Intricately who was ridden to success in the Moyglare Stud Stakes at the Curragh by Donnacha.
Joseph has continued to make relentless progress since that memorable day, with his tally of winners both on the Flat and over jumps increasing markedly in 2017. A wonderful year was capped in the best possible style by the remarkable win of Rekindling in the Melbourne Cup at Flemington in November, a feat that generated headlines all over the world and announced Joseph’s arrival as an international force in Flat racing.
The 2017/18 National Hunt season saw him reach more milestones, with him training his first Grade 1 winners since taking out his license during the Dublin Racing Festival at Leopardstown courtesy of Tower Bridge in the Nathaniel Lacy & Partners Solicitors Novice Hurdle and Edwulf in the Irish Gold Cup.
Joseph achieved another first during the 2018 Flat season when teaming up with Donnacha to secure his first Classic winner as a trainer courtesy of LATROBE in the Irish Derby at the Curragh.
His win with IRIDESSA in the 2019 Breeders Cup Filly and Mares turf (Grade 1) at Santa Anita, make him only the second person to have both ridden and trained a winner at the prestigious and very valuable annual Championships in the US.