Ridden by Bill Hartack, Decidedly set a new Churchill Downs track record for 1¼ miles in winning the 1962 Derby. In the second leg and third legs of the U.S. Triple Crown series, the Preakness and Belmont Stakes, he was unplaced.
In 1963 Decidedly won five of thirteen starts and set a new Keeneland track record for 1/16 miles in winning the Ben Ali Handicap. He was retired from racing at age five after the 1964 season in which he won two races from ten starts.
At stud, Decidedly was the sire of of nineteen stakes race winners.