He was bred and raced by Gladys Phipps and her brother Ogden L. Mills under their Wheatley Stable banner.
Among his wins, Successor defeated the previously unbeaten Dr. Fager by a length to earn a victory in the Champagne Stakes, recording the second fastest time in the race's history.
Unplaced in the Blue Grass Stakes, Successor finished sixth to winner Proud Clarion in the Kentucky Derby.
The colt went on to earn two seconds and two third-place finishes in major races that year and scored a popular win[3] on October 18 in the 1 5/8 mile Lawrence Realization Stakes.
On February 17, 1968 Successor was sold for $1,050,000 to Hastings Harcourt's Flag Is Up Farms in Solvang, California.