Trained by Don Cameron and ridden by future Hall of Fame inductee Longden, as a two-year-old Count Fleet started off slow losing several times before getting his first win. He gained respect with his six length victory in the Champagne Stakes, in which he set a new track record then followed this up by beating the best horses in the country in the Pimlico Futurity where he equaled the track record. In the Walden Stakes, he ran away from the field, winning by more than thirty lengths. At season's end, he had won ten of his 15 races while never being out of the money, a performance that earned him the two-year-old championship honors.
As a three-year-old, Count Fleet dominated North American racing, never losing a race. Leading up to the Kentucky Derby he won the important Wood Memorial but injured himself in the process. He recovered to take the United States most prestigious race by three lengths then went on to Baltimore, Maryland where he dominated the Preakness Stakes, taking that one by eight lengths. He then won the Withers Stakes before heading to Elmont, New York for the Belmont Stakes where he captured the Triple Crown by scoring an amazing 25 length victory, a margin record that stood until 1973. When the season ended, Count Fleet was voted Champion 3-year-old and named American Horse of the Year.
Rather than risk serious injury, Count Fleet did not race as a four-year-old after it was discovered that he had injured his leg close to the joint between the cannon bone and the fetter bone. He was retired to stud having won 16 of 21 races and went on to enjoy great success as a sire. His offspring numbered 38 stakes winners, including Kentucky Derby winner Count Turf, Belmont Stakes winners Counterpoint and One Count, Horse of the Year champions, and a Champion Three Year Old Filly. Count Fleet's daughters produced superhorse Kelso, 1965 Kentucky Derby winner, Lucky Debonair, and multiple Grade I stakes winner, Tompion. Another daughter, Sequence, mated with 1955 Preakness and Belmont winner Nashua to produce Gold Digger, dam of the enormously influential modern sire Mr. Prospector.
In 1961, Count Fleet was inducted in the National Museum of Racing and Hall of Fame.
Count Fleet died on December 3, 1973 and was buried at Stoner Creek farm in Paris, Kentucky.
In the Blood-Horse magazine ranking of the top 100 U.S. thoroughbred champions of the 20th Century, Count Fleet was ranked #5.