She made her debut appearance in The Water Flowers of Cerulean City along with Misty's other sisters. She and her sisters participates in the water shows hosted by the Cerulean Gym. She is also one of the three temporary Leaders of Cerulean Gym. She, along with her other two sisters, refused to battle with Ash Ketchum due to their Pokémon being injured from their defeats against the other three trainers from Pallet Town. The only remaining Pokémon that was healthy enough to battle was a Goldeen that Lily owned.
She, Daisy, and Violet were mentioned in Just Add Water by Dorian.
In Gotta Catch Ya Later!, she left on a cruise with her sisters and leaving Misty to take temporary charge of the Gym.
She made many more appearances along with Daisy and Violet in future episodes as well as in the Pokémon Chronicles.
Lily and Violet tend to tease Misty more than Daisy does. Throughout The Water Flowers of Cerulean City, she often teases Misty for not being as strong a trainer as they are and not being as pretty. She labels Misty as a runt in comparison to being one of The Sensational Sisters. She also tends to upset Misty by saying that she is not as talented a trainer as they are. This drives Misty to leave Cerulean City in order to become a better trainer. She doesn't believe Misty to be a powerful trainer and shows she has no faith in Misty during the start of her gym battle with Ash. Over the period of the battle however, she does admit that Misty does have some talent as a Pokémon trainer. When Ash and Misty set out on their journey, she encourages Misty to become a strong trainer so that she can become good at something.
She, along with her other sisters, care mostly about how she looks. They showed this by caring more about their hair than their Pokémon during the Team Rocket attack. They don't like losing to the challengers at their gym and would rather just give away their gym badge instead of losing. She and Violet enjoy teasing Misty often. She and her sisters love Misty very much and encourage her to become a strong trainer despite all of their comments. In the anime she is seen to be very childlike and carefree. During the water shows hosted by the gym, she is also shown to prefer to play boyish roles whereas Violet plays the more girlish ones.
Lily has pink hair and blue eyes. She is first seen wearing an orange swimsuit throughout the duration of her debut episode.