Seattle Slew made his first start in a six-furlong maiden race on September 20, 1976, the fifth race at Belmont Park on Long Island, New York.
Seattle Slew went off as the odds-on 1-2 favorite in the 1¼-mile Kentucky Derby on May 7. A "speed horse" who normally broke well and went right to the lead, he swerved at the start and was taken up by jockey Jean Cruguet.