The eldest son of Irish champion trainers Aidan and Annemarie, Joseph O’Brien has wasted little time in establishing himself as an integral part of the Ballydoyle operation.
He started off riding at pony clubs and won a bronze medal at the 2009 European Pony Championships before deciding to concentrate on becoming a Flat jockey shortly afterwards.
O’Brien enjoyed his first winner on board Johann Zoffany (later renamed Muir after being sold to race in Australia), trained by his father, at Leopardstown on 28 May 2009 and was joint champion apprentice in a three-way tie with Ben Curtis and Gary Carroll in 2010.
Things got even better in 2011, with a first Classic success on Roderic O’Connor in the Irish 2000 Guineas, two days before his 18th brithday. He won three other Group 1 races that season, the Moyglare Stakes on star two-year-old filly Maybe, the Racing Post Trophy on the season's joint top two-year-old, Camelot, and the Breeders' Cup Turf in the USA on St Nicholas Abbey.
He started 2012 in a similar vein as Camelot provided the jockey with a first British Classic success with a neck verdict in the QIPCO 2000 Guineas, the first contest in the QIPCO British Champions Series, at Newmarket on May 5.
On June 2, he landed his second Classic on Camelot when the Montjeu colt was an impressive winner of the Investec Derby. In the process, O'Brien created history as no father/son combination of jockey/trainer had previously landed the Classic. Camelot attempted to land the Triple Crown, but was beaten into second in the Ladbrokes St Leger at Doncaster on September 15.
His career continues to progress at an astonishing rate and on June 20 he recorded a first victory at Royal Ascot aboard So You Think in the Group 1 Prince Of Wales's Stakes.
A fifth 2012 victory in the QIPCO British Champions Series came courtesy of Excelebration in the Group 1 Queen Elizabeth II Stakes Sponsored By QIPCO - a success that saw O'Brien take the title of Jockey of the Series.
His first Series win in 2013 came on St Nicholas Abbey in the Investec Coronation Cup, with the horse making history by winning the race for the third time, and he followed up in the opener at Royal Ascot when Declaration Of War won the Queen Anne Stakes, before riding that horse into second place in the Coral-Eclipse and then after third place in the QIPCO Sussex Stakes, the partnership came good again in the Juddmonte International with a fine victory over Trading Leather and Al Kazeem.
He then won his first Ladbrokes St Leger, making up a little for Camelot's defeat 12 months earlier, when bringing Leading Light home in front of Talent and Galileo Rock. It was his fourth Series victory of the season and his ninth overall, but it was not enough to see him crowned Jockey of the Series for a second time - he finished a close third behind Richard Hughes and Johnny Murtagh.
He rode Australia into third place in the QIPCO 2000 Guineas and then he won the race he was destined for, the Investec Derby. Next he won the Gold Cup on Leading Light, just getting the better of last year's winner, Estimate. He then rode Australia in the Juddmonte International and won with ease.
QIPCO British Champions Series victories
2012 (5 wins)
QIPCO 2000 Guineas, Newmarket - Camelot
Investec Coronation Cup, Epsom - St Nicholas Abbey
Investec Derby, Epsom - Camelot
Prince of Wales's Stakes, Royal Ascot - So You Think
Queen Elizabeth II Stakes, Ascot - Excelebration
2013 (4 wins)
Investec Coronation Cup, Epsom - St Nicholas Abbey
Queen Anne Stakes, Royal Ascot - Declaration Of War
Juddmonte International, York - Declaration Of War
Ladbrokes St Leger, Doncaster - Leading Light
2014 (3 wins)
Investec Derby, Epsom Downs - Australia
Gold Cup, Royal Ascot - Leading Light
Juddmonte International, York - Australia