Bred and raced by Fred F. Bradley of Frankfort, Kentucky, Brass Hat is trained by his son William "Buff" Bradley. After a successful three-year-old season in 2004, Brass Hat won once in two starts in 2005. In 2006 he won two of four starts. He set a new Gulfstream Park track record of 1:47.79 for 9 furlongs in the Grade I Donn Handicap. He finished second to Electrocutionist in the March 25th Dubai World Cup but was disqualified after a post-race test revealed trace amounts of the banned drug methyl prednisolone acetate. While owner Fred Bradley did not dispute the positive test, he asserted that the therapeutic medication given the horse 28 days prior to the World Cup was well within the guidelines put out by the Emirates Racing Association. The disqualification was upheld on appeal. In mid summer, Brass Hat suffered a sesamoid fracture that kept him out of racing for several months.
Returning to the track in 2007, Brass Hat set another track record at Churchill Downs, winning an 8.5 furlong race in 1:41.27. He then finished eighth in the Whitney Handicap and sixth in the Woodward Stakes at Saratoga Race Course but returned to winning form in September when he captured the Massachusetts Handicap.