Of Jessop's four mounts in the Kentucky Derby, his best result was two third-place finishes. In 1946, he was third on Hampden behind eventual Triple Crown winner, Assault. Guiding the great Hall of Fame mare Gallorette, he won the Queens County Handicap against male horses in 1947.
Jessop's most successful results in the Kentucky Derby were two second-place finishes. In 1946, he finished third on Hampden behind Triple Crown winner Assault. With Hall of Fame mare Gallorette, Jessop won the Queens County Handicap against male competitors in 1947.