2003: Two-year-old season She won her debut in a Maiden Special Weight at
Del Mar Racetrack, and then defeated five opponents
Grade 1 Del Mar Debutante Stakes including Hollywood Story and Victory USA. She then won the
Grade 2 Oak Leaf Stakes at
Santa Anita Park, a prep for the
Breeders' Cup World Championships. She faced six rivals including Hollywood Story again. Entering the
Breeders' Cup Juvenile Fillies undefeated, Halfbridled started as the 2-1 favorite in a field of fourteen. She drew the farthest post from the rail, #14. She won under her usual jockey, Hall of Fame rider
Julie Krone. Halfbridled was named the
Eclipse Champion 2-Year-Old Filly.
2004: Three-year-old season Halfbridled made her sophomore debut in the
Santa Anita Oaks, finishing second behind Composure. Next she contested the
Beaumont Stakes, again finishing second in what was her final race. After the Beaumont Stakes, it was discovered that Halfbridled had sustained an injury to her canon bone and would be sidelined for the rest of the season. The following November, after supposedly healing from her injury, Halfbridled returned to training to prepare for the 2005 racing season. During a gallop it was realized that the filly never truly healed from her injury, and the decision was made to retire her. ==Breeding career==