As the half brother to 2009 Kentucky Derby winner Mine That Bird, Dullahan had a pedigree that made him a prospect for America's Triple Crown races, but his best career performances have come on synthetic surfaces. His first career victory came on the Polytrack surface at Keeneland in the Breeders' Futurity in October. He finished fourth in the Breeders' Cup Juvenile at Churchill Downs on November 5. Dullahan returned from a break from competition on March 11 to finish second by a length in the Palm Beach Stakes on turf at Gulfstream Park before acing his final Kentucky Derby prep by defeating champion Hansen in the Blue Grass Stakes on the Keeneland Polytrack.
In the 2012 Kentucky Derby, Dullahan closed gamely to finish third behind winner I'll Have Another and runner-up Bodemeister. He confirmed his elite class with a win against older horses in the Pacific Classic Stakes (G1) at Del Mar in August.
Donegal Racing purchased Dullahan for $250,000 at the 2010 Keeneland September yearling sale. His sire is Even the Score, a son of Unbridled's Song, and he is out of the Smart Strike mare Mining My Own. In the Irish fairy realm, a dullahan is a black-robed horseman who carries his severed head.