In 1975, the twenty-year-old McHargue earned the most important win of his career when he rode Master Derby to victory in the Preakness Stakes, the second leg of the U.S.
A proven rider on turf, in 1983 McHargue moved to a base in Ireland, where he rode for various trainers including Luca Cumani and Dermot Weld and for owners such as the American husband and wife team of Bertram and Diana Firestone and Englishman Ivan Allan.
In 1984, he was the stable jockey for Cumani and had ridden Allan's outstanding colt Commanche Run in most of his races .
Commanche Run had, however, put up a vastly improved performance in the Gordon Stakes under Lester Piggott when McHargue was suspended .
[2] McHargue retired from riding in early April 1988 and began a new career a few weeks later as a racing official.