He was a bay son of the great Northern Dancer and the very speedy racing mare Drumtop.
[1] Topsider won eight races from eighteen career starts, including the Sport Page Handicap at Aqueduct Racetrack in New York City.
[2] In another of his wins he set a new track record of 1:14 2/5 for 6½ furlongs at Saratoga Race Course.
When his racing career was over, Topsider was sent to Claiborne Farm in Kentucky where became a significant sire whose offspring won more than $18 million in racing.
Topsider stood his entire career at Claiborne Farm and died there on October 18, 1992 as a result of a hernia in his diaphragm.