Cissy made her anime debut when Ash challenged her for the Coral-Eye Badge in Fit To Be Tide.
Ash discovered that Cissy, like the rest of the Orange Crew, conducts a different kind of Gym battle than what he was used to in the Indigo League. The first part of the match is an accuracy test where both Trainers have their Pokémon use Water Gun to accurately hit targets. The second test is a surfingrace around some buoys near the coast. Ash prevailed in both challenges and won the Badge.
She reappeared in flashbacks in A Way Off Day Off, Hello, Pummelo! and Viva Las Lapras.
According to Tracey, Cissy is known as "one of the toughest Trainers in the Orange Crew." She specializes in Water-type Pokémon, and one of the rules of her Gym is that her opponents are required to use Water-type Pokémon as well.
She lives with her assistant and little brother, Senta, who is also a Pokémon Trainer.