Bred by John E. Madden, the bay colt (soon to be gelded) was out of the stallion, Uncle's, first crop. Born in Kentucky, he was purchased as a yearling for $500 by the trainer Frank D. Weir. Weir then sold a majority interest in the gelding to the treasurer of Churchill Downs, Hamilton C. Applegate. Frank Weir said of the gelding, "Old Rosebud was the kind of horse one sees once in a lifetime. He certainly was the fastest horse I ever trained or saw. If he had been sound, there's no telling how fast he would have run."
But that was the trouble. All his life, Old Rosebud was plagued by ailments. His courageous career ended when he died on the track in a lowly claiming race, yet he was still one of the Great Horses...and he did it game. Old Rosebud was all heart.
He began by being the two-year-old champion of 1913 and top earner for the year. At two, Old Rosebud's most important victories included the Flash Stakes and the United States Hotel Stakes. Before his first injury took him out of training, he'd set four track records.
He came back in his third year to take the 1914 Kentucky Derby by eight lengths in a time of 2:03 2/5, setting a record that would not be broken for 16 years.
Old Rosebud broke down in his next race. It was only three weeks after the Derby, and he'd been entered in the Withers Stakes at Belmont Park (where races were still being run clockwise in the English fashion). Running the wrong way confused the horse who did not change leads coming into the stretch. He came out of the Withers in May 1914 with a bowed tendon, and was taken out of competition for two seasons.
At 6, after nearly 3 years on the prairies of Texas, and refuting the old saw that "they never come back," Old Rosebud won the Queen's County, the Carter Handicap, the Red Cross, and the Delaware Handicap. He was also named Champion Handicap Male of 1917. But once again injury took him out of competition for another year and a half.
Old Rosebud returned to racing at the age of 8. He competed for four more years before suffering his final fatal injury in a claiming race at Jamaica Racetrack. It was 1922 and Old Rosebud had been racing for ten years.
Gallant Old Rosebud won the Yucatan Stakes, the Spring Trial Stakes, the Harold Stakes, the Cincinnati Trophy Stakes, the Flash Stakes, the United States Hotel Stakes, and then the Kentucky Derby. In the Derby, he went off as the favorite. He went on to win the Clark Handicap, the Latonia Inaugural Handicap, the Queens County Handicap, the Carter Handicap (again), the Frontier Handicap, the Delaware Handicap, the Bayview Handicap, the Mt. Vernon Cap, the Sir Archy Highweight Cap, and the Latonia Grand Hotel Purse.
He came in second in the Idle Hour Stakes, the Bashford Manor Stakes, the Paumonok Handicap, the Mount Vernon Handicap (losing to the 4 years younger August Belmont, Jr.'s Lucullite, but beating Sun Briar, Exterminator's stablemate), and the Burnett Woods Cap (to the five years younger stakes winning Sennings Park).
In 1968, Old Rosebud was elected to the National Museum of Racing and Hall of Fame.
Out of 80 Starts, he won half, a full 40, placed in 13, and showed in 8. His career earnings stood at $74,729 at the time of his death.