
The horse racing industry has long been rife with families that pass it down from generation to generation. The modern version of the sport is just as guilty, with some of the best names in the business being the offspring of others. Elsewhere we’ve written about the likes of Ruby Walsh, his dad, Ted, and his sister, Katie, for example.
Here we’ll have a look at the O’Brien family, which is perhaps best known because of Aidan O’Brien, the trainer extraordinaire. As with other horse racing dynasties, though, he’s not on his own as being a talented member of the O’Brien family. Here’s a look at the other people in his family tree
The O’Brien Family Tree
Anne-Marie, Aidan O’Brien’s wife, came from a horse racing family that was, in many ways, responsible for the man himself getting involved with the industry. Her father, Joe Crowley, was a well-known trainer of horses in Ireland and Anne-Marie eventually took over from him before giving the responsibility for the stables to her husband.
The O’Briens had four children and they all went into horse racing in one form or another. Both Anastasia and Sarah O’Brien enjoyed minor successes, with Donnacha following in their footsteps when he notched up his first win in 2014. Yet it’s Joseph O’Brien that has been the most successful of the children, winning the Derby in 2012 on the back of Camelot.
Famous Members
Having gained something of a more general feel for the O’Brien family, let’s take a deep-dive on the various family members and explore their achievements to date.
Aidan O’Brien

Born Aidan Patrick O’Brien on the 16th of October in 1969, Aidan was one of six siblings born to Denis and Stella O’Brien. Born and raised in County Wexford, Ireland, Aidan didn’t really get his horse training bug from his parents. Denis was a trainer on a small-scale as Aidan was growing up, but he was mostly a farmer in the townland of Killegney, which is close to Poulpeasty in Ireland.
It wasn’t until he began working with P.J. Finn at his stables in the Curragh, County Kildare that he truly got the bug. He soon moved on to work with Jim Bolger at his stables in Coolcullen, County Carlow. He learnt the trade with those two, with Jim Bolger in particular being a big name in the industry at the time, seeing the likes of Tony McCoy and Paul Carberry work as apprentices for him before they became household names in their own right.
Anne-Marie
When he met Anne-Marie Crowley, who would later become Anne-Marie O’Brien when the pair married, he began to gain more experience on her father’s stables in Piltown, County Kilkenny. She took over from Joe Crowley and made a success of it, before Aidan took over from her in 1993. He was only in charge of the stables for two years before he moved onto Ballydoyle and Anne-Marie’s sister, Frances, took on the responsibility.
Ballydoyle
Ballydoyle is the main training facility in County Tipperary, which created in the wake of the Cheltenham Festival in 1951. It was the brainchild of Vincent O’Brien, though it’s worth pointing out that he’s no relation to Aidan. It is the sister facility of Coolmore, with both places being owned by Vincent O’Brien’s son-in-law, John Magnier.
Desert King
Far from being cowed by the prospect, Aidan O’Brien embraced it and set about implementing his own training methods in order to influence the Ballydoyle stables as best he could. It didn’t take him long to register his first major success, winning the Group 1 National Stakes at the Curragh with Desert King in 1996.
It was a horse that would prove to be influential to O’Brien’s career, bringing him his first success in a Classic when it won the 2,000 Guineas the following season. In the years that followed, Aidan’s influence on racing grew and grew, so that hardly anybody was surprised when he was declared to be the Champion Trainer in England in 2001, becoming the first Irishman since Vincent O’Brien in 1971 to be given the award.
Keiren Fallon
After a disappointing season in 2004, Keiren Fallon was brought on board as the stable jockey and he and O’Brien hit it off straight away. In the first weekend of Classic races that year, the pair took home both the 1,000 and 2,000 Guineas thanks to Fallon’s exceptional riding of Virginia Waters and Footstepsinthesand, respectively. As the season wore on, the top-notch wins kept on coming, with the Eclipse Stakes, Irish Champion Stakes, St. Leger and Grand Prix de Paris all being added to O’Brien’s list of wins.
Notable Victories
The year after saw O’Brien retain the 2,000 Guineas when George Washington gave him his fourth win in the race. The same horse then went on to win the prestigious Queen Elizabeth II Stakes at Ascot. When Alexandrova won the triple of the Oaks, the Yorkshire Oaks and the Irish Oaks in the same season, O’Brien’s reputation as a top-class trainer of flat racing horses was well and truly set in stone. Ironically, the following year was a difficult one for the stable, not least because of Fallon’s suspension from racing after race-fixing allegations were levelled at him.
As the 2007 season wore on, however, O’Brien’s charges began to find their feet again. He achieved a 1-2-3 finish in both the St. James’s Palace Stakes and the Irish Derby. He notched up four wins at Royal Ascot too, finishing the event as the top trainer. Keiren Fallon’s ban in Europe was eventually lifted and he returned to action in style, winning the Prix de l’Arc de Triomphe on Dylan Thomas. It was only the premature demise of George Washington after he broke down in the Breeders Cup Classic that put a sour note on the year.
In 2008, Fallon was replaced by Johnny Murtagh as Ballydoyle’s stable jockey, helping O’Brien to beat a record that was set in 1935 when he became the first trainer since then to win all five of the Irish Classics. He also equalled a record previous set by Vincent O’Brien when he saw six of his horses win races at Royal Ascot, including the Ascot Gold Cup that Yeats won for the third year in succession. Eight years later O’Brien would go on to beat his own record when he won seven races during the Royal Ascot meeting.
World Record Winner
Perhaps one of the most interesting things about O’Brien is that he showed no signs of slowing down as he grew older. In 2017, for example, he set a world record by winning twenty-eight Group and Grade 1 races.
Despite all the talk of his successes on the flat, O’Brien has also seen a number of his horses win over jumps. He trained Istabraq, for example, who won the Champion Hurdle three times in succession between 1998 and 2000. He has had a number of winners at the Cheltenham Festival, including seeing Istabraq and Urubande win the Baring Bingham Novices’ Hurdle.
Yet there’s no question that it’s on the flat where his true talent lies. The list of prestigious flat races that horses trained by O’Brien have won it eye-watering. From the likes of the Coronation Stakes and the King George VI and Queen Elizabeth Stakes through to the St. Leger and both the 1,000 and 2,000 Guineas, Aidan O’Brien has put his stamp firmly on the world of flat racing over the years. That’s only to talk about the races in the UK, of course. Look further afield to the United Arab Emirates, Italy and, of course, Ireland and the list grows even longer.
Joseph O’Brien

Joseph Patrick O’Brien was born on the twenty-third of May in 1993 and began his racing life riding ponies. In 2009, he was awarded a bronze medal at the European Pony Championships, for example. He made the turn to horse racing and notched up his first win in the same year when he took Johann Zoffany across the finish line first at Leopardstown.
It didn’t take Joseph long before he was winning regularly, sharing the Irish Champion Apprentice Jockey title with two others in 2010. The year after, he won the Irish 2,000 Guineas on Roderic O’Connor, registering his first success in a Classic. That was good preparation for what was to come, with O’Brien teaming up with his father in 2012 at the age of just nineteen to become the first father-and-son jockey-and-trainer combo to win the Derby when he was victorious on the back of Camelot.
Irish Champion Jockey
He managed eighty-seven wins that season to earn himself the title of Irish Champion Jockey. In 2013 he won a treble at Navan to notch up one hundred and seventeen winners for the season, breaking a record for a twenty-year-old previously set by Mick Kinane. He ended up winning one hundred and twenty-six times that season, unsurprisingly retaining his Irish Champion Jockey title.
Given the success of his father, it’s not entirely shocking that O’Brien had half an eye on working as a trainer. In March of 2016, he announced that he would be doing exactly that, stepping down as a jockey to focus on the other side of his career. He began learning the ropes at Owning Hill in County Kilkenny and achieved almost instantaneous success when Intricately was victorious in the Moyglare Stud Stakes. The year after he won the Melbourne Cup and then, in 2018, Latrobe gave him a victory in the Irish Derby.
Donnacha O’Brien
Whilst none of the O’Brien children have come close to replicated the success of Joseph, Donnacha O’Brien is probably the most likely to do so. The youngest of the group, he was born on the twenty-second of July 1998.
Given the success of his father and brother, it was clear that Donnacha would follow in their footsteps. He notched up his first win as a flat racing jockey when Quartz won for him at Dundalk Stadium in September of 2014. It took him another two years to see victory in a Classic, winning the Moyglare Stud Stakes in 2016.
Given that this piece is all about keeping it in the family, it’s entirely fitting that O’Brien’s steed for the Moyglare Stud Stakes was Intricately, which was bred by his mother and trained by his brother. The win helped him on his way to becoming the Irish Flat Racing Champion Apprentice Jockey that year. He didn’t rest on his laurels, though, and a win in the Irish Derby in 2018 on the back of Latrobe, also trained by his brother, was part of the reason for him being named the Irish Flat Racing Champion Jockey in 2018.
Other Family Members
As mentioned a number of times in this piece, Aidan O’Brien’s wife, Anne-Marie, is a respected breeder in her own right. That’s no surprise, of course, given that her father was the man who gave Aidan a real taste of the breeding life.
Anastasia and Sarah O’Brien, the sisters of Joseph and Donnacha, have also raced as jockeys. Whilst neither of them have managed the same level of success as their two brothers, or of course their father, they’re still worthy of a mention when discussing the world of racing and the link of the O’Brien family to it.