Carrie Kastroll, an accomplished horsewoman, died on July 15 in Sydney, Australia, from complications associated with Wilson’s disease. She was 39.

Ms. Kastroll’s riding career began along the wooded trails of Sewickley Heights, Pa. As a child, she joined the Sewickley Hunt where she won the Black Award as the best junior rider.

Her equestrian skill was apparent from the beginning when, as a student at Sewickley Academy, she won dozens of blue ribbons in horse shows. “Carrie refused to stop there,” her mother, Carolyn Smith, said. “She graduated from the Academy on a Friday and was riding professionally in Florida the following week.”

Ms. Kastroll enjoyed particular success in her late 20s, winning championships at major horse shows such as the Winter Equestrian Festival circuit (Fla.), the Washington International (D.C.) and the Devon Horse Show (Pa.). In 1995, she was honored as the Virginia Horse Shows Association Horseperson of the Year.

Flawless movement and unflagging determination, qualities present since childhood, became the foundation of her riding style. Whether showing or simply exercising her mount, Ms. Kastroll always displayed a casual but cool demeanor.

Chronic injuries led Ms. Kastroll to retire from riding professionally and she began her new career as an instructor. In 2000, she moved to the East Coast of Australia, near Coffs Harbour, where she trained young riders.

Ms. Kastroll is survived by her parents, Carolyn and Bud Smith, and siblings Will Kastroll, Jennifer McTiernan and Jeffrey Smith. Memorial donations may be made to the Wilson’s Disease Association, 1802 Brookside Dr., Wooster, OH 44691.