Birthdate: October 16, 1969
Birthplace: County Wexford, Ireland
Residence(s): Ballydoyle, Cashel, County Tipperary, Ireland
Family: Wife, Anne-Marie; children, Joseph (now riding for his father), Sarah, Anna and Dennis
Aidan O’Brien was the son of a farmer and small-time trainer who apprenticed with Jim Bolger for three years before taking over the racing license of his wife, champion jumps trainer Anne-Marie, daughter of trainer Jim Crowley, in 1993. O’Brien secured champion amateur riding honors over the jumps the following year at age 23, and went on to champion jumps trainer for five years while also training on the flat. He shifted to training only flat horses after the retirement of his top jumper Istabraq in 2000.
Backed by the Coolmore operation, O’Brien has rewritten the record books since he became the youngest champion trainer in 1996, his second year headquartered at storied Ballydoyle in County Tipperary. His many training championships since — deserved for the multiple wins in each of the classics in Europe, multiple Breeders’ Cup victories, and successes in other top races in Europe and North America — have been earned by his rarely relaxing his famous focus. O’Brien leaves his Ballydoyle operation as close to a race as possible and returns right afterward. However, he has enjoyed taking his kids to Disneyland following Breeders’ Cups at Santa Anita Park.
O'Brien won his second straight U.A.E. Derby with Lines of Battle in 2013, cementing both horse and trainer a spot in the Kentucky Derby. O'Brien has started four horses in the Derby with his best finish coming from Master of Hounds, who finished fifth in the race.