In his first start, a maiden special weight on the Travers undercard at Saratoga, Uncle Mo led at every call to beat a field of 2-year-olds by 14 1/4 lengths.

Triple Crown series,[3] Uncle Mo made his 3-year-old debut in the Timely Writer, a one-turn mile overnight stakes at Gulfstream Park.

After finishing a course of antibiotics, regressing immediately after stopping medication, and losing over 70 pounds in the weeks before the Derby, he was scratched the day before the race.

[5] Sent to Winstar Farm to recuperate and receive attention from top veterinarians, Uncle Mo was diagnosed with cholangiohepatitis, a rare liver disease.

His retirement was prompted due to elevated levels of the liver enzyme GGT, which also occurred earlier in the season and led to a diagnosis of cholangiohepatitis.