Historically the ISH was bred by crossing Irish Draught and Thoroughbred stock, and the breed was formalised in the 1920s.

It has good bone, a short back and strong loins, muscular hindquarters, a sloping shoulder, deep chest, and a long neck.

[8][4][9] According to Emily Donoho, "while [adding warmbloods] increases genetic diversity and gets more Irish horses in the showjumping ring, some competitors and breeders are concerned that the traditional TB-ID lines are being lost".

[5] A report from a study of Irish Draught genetics recognized the importance of ID genes in producing high quality contemporary sport horses, however it pointed out the difficulties because of the small population size of the endangered Irish Draught, and the problems of dilution on second and third generations without additional infusion of ID blood.

[b][8][5][16] According to Donoho, the ISH "dominates eventing" including at such top level competitions at Badminton, Burghley, the Olympics, and world championships.