MacPherson competed for Canada at the 1984 Summer Olympics in Los Angeles, California. She was able to win a bronze medal for Canada in the 4×100 m medley relay with Anne Ottenbrite, Reema Abdo, and Pamela Rai. She set a Canadian record in the 200 m individual medley that year. She also won three silver medals for Canada at the 1983 Pan American Games in the 100 m butterfly, 200 m medley, and the 4x100 m medley relays, as well as a bronze medal in the 400 m medley.