Big Pebble was a bay horse bred by Edward R. Bradley at his Idle Hour Stock Farm near Lexington, Kentucky.
For his new handlers, Big Pebble developed rapidly into a contender, running a strong second to Many Stings in the March 1940 Widener Challenge Cup at Florida's Hialeah Park Race Track.
Back at Hialeah Park for winter racing, he won a division of February's McLennan Handicap and then the prestigious Widener Challenge Cup in March.
Big Pebble's 1941 performances earned him American Champion Older Male Horse honors from Turf & Sports Digest magazine.
On November 26, 1941, owner Edward S. Moore announced that Big Pebble was being retired to stand at stud due to a bowed tendon.