After showing promising form as a two-year-old she improved to be the best female racehorse of her generation for the next three seasons.
Princess Doreen was a bay mare bred by John E. Madden at his stud farm, Hamburg Place, in Kentucky.
She was sired by Spanish Prince, a British horse which won several major sprint races between 1910 and 1913 including the King's Stand Stakes at Royal Ascot and two editions of the July Cup.
In October 1924, Princess Doreen participated in what was called the International Special, where three races would take place.
Upon retiring, Princess Doreen was America's leading female money winner, toppling Miss Woodford's record.