Owned by Winchell Thoroughbreds and Three Chimneys Farm and trained by Steven Asmussen, Gun Runner was a late-maturing type, who did not win his first Grade One race until the final start of his three-year-old campaign. However, the son of Candy Ride won five of his six starts as a four-year-old, including the Breeders’ Cup Classic at Del Mar, and was named American Horse of the Year in 2017.
Gunner Runner raced just once as a five-year-old, but his convincing 2½-length victory over West Coast in the Pegasus World Cup at Gulfstream Park – the most valuable race in the world – earned him £5.19 million and made him the third highest-earning racehorse in history, behind only Arrogate and Winx. All told, Gun Runner won 11 of his 18 starts, including six at Grade One level, and retired from racing with total earnings of £12.2 million.
Gun Runner raced just twice as a juvenile, making an impressive winning debut in a maiden race at Churchill Downs in September, 2015 and finishing a close fourth in the Grade Two Kentucky Jockey Club Stakes, on sloppy going, on the same course two months later. As a three-year-old, he won twice at Grade Two level and once at Grade Three level, but came up short in the Kentucky Derby at Churchill Downs, the Travers Stakes at Saratoga and the Breeders’ Cup Dirt Mile at Santa Anita before his ‘breakthrough’ victory in the Grade One Clark Handicap at Churchill Downs.
Following an impressive, 5¾-length win, at odds of 1/5, in the Grade Three Razorback Handicap at Oaklawn Park on his four-year-old debut, Gun Runner proved no match for Arrogate in the Dubai World Cup at Meydan, but finished clear second and collected £1.63 million in prize money. Other notable performances that season included a 7-length win in the Grade One Stephen Foster Handicap at Churchill Downs and a 10-length win in the Woodward Stakes at Saratoga; the former came within a whisker of breaking the track record and the latter, achieved in a time of 1 minute 47.43 seconds, was the fastest recorded in a dozen renewals of the race at the New York venue.