John Henry is a thoroughbred race horse named after the folk hero John Henry. He is a gelding. A foal of 1975, John Henry was from breeding that might best be described as plebian. His sire, Ole Bob Bowers, once sold for just $900, and was not in much demand by breeders; his dam, Once Double, was an undistinguished runner and producer, but was sired by Double Jay, who had proven to be a useful broodmare sire.

John Henry was sold as a yearling for $1,100 at the Keeneland January Mixed sale. From there, he was shuffled around through a series of owners and trainers, making his mark as a workmanlike racehorse who earned money in minor stakes, allowance races and mid-level claiming races.

In 1979, John Henry was sent to trainer Ron McAnally in California. Whether it was hall-of-famer McAnally's handling of him, the change of scene from the east coast to the tracks in California, or just that the late-maturing John Henry was finally coming into his own as a racehorse cannot be determined; but it was at this point that the small, plain, dark bay or brown gelding started hitting his stride.

Racing through the age of 9, John Henry became a force to be reckoned with in the handicap and turf stakes races of the time. He twice won the Santa Anita Handicap (once by disqualification); twice won the Arlington Million Stakes; his final race record stood at 83 starts, 39 wins, 15 seconds, and 9 thirds with $6,497,947 in earnings. He was twice voted Horse of the Year.

John Henry's owner, Sam Rubin, sent the horse to the Kentucky Horse Park in Lexington to live in the Hall of Champions barn there, sharing company with other retired champions. In the annals of racing, John Henry earned his place of greatness through toughness, tenacity, and hard work rather than intrinsic brilliance.

John Henry, in the view of many followers of thoroughbred racing, was one of the best come-from-behind horses (or "closers") in recent history.