Pearson made her international debut at the 1978 Commonwealth Games in Edmonton, Canada, where she finalled in both the 200-metre and 400-metre individual medleys, finishing seventh and fifth respectively.

She was a part of the 4×100-metre freestyle relay team along with Lisa Curry, Rosemary Brown and Karen van de Graaf, which placed fifth in the final.

At the 1982 Commonwealth Games in Brisbane, Pearson collected her first international medals, winning silver and bronze in the 400-metre and 200-metre individual medley respectively.

Pearson had a good preparation for the 1984 Summer Olympics, after winning two events at the United States Championships as a guest competitor.

In the 200-metre individual medley, she trailed home the American duo of Tracy Caulkins and Nancy Hogshead, edging out Curry by 0.83 of a second to claim the bronze medal.