Married to Freddie Femur the spritely Casey is the embodiment of liveliness.
When she initially meets Francine, she is introduced to her as Freddie's new girl-friend,she shows no animosity toward her and even genuinely offers to help her lose some weight. Unfortunately this was a bad time for Francine and devastated her. Nevertheless they became good friends even if they sometimes have to tolerate her fragile nature and seemingly random outbursts of inappropriate displays of passion.
After the incident in the art gallery she decides that David was coming onto her, when really it was all on her side, and goes to visit him. She jumps on him and tries to seduce him ripping both their clothes off. Katchoo, who is in the house, interrupts and she breaks down because Freddie is infatuated with Francine and pays her no attention.
She is there when David receives the phone call that tells him he is a billionaire and immediately asks him to make love to her in front of Katchoo. When Katchoo and David go and lie down in a darkened bedroom she starts to cry, but rallies and strips naked and asks if she can join in. The pair are actually clothed and when Francine arrives home the dressed David and naked Casey hide in a bathroom and come tumbling out when Casey tries to kiss him again against his wishes.
She goes to Vegas to become a show girl.
At the end it is revealed she has been a plant of Tambi's watching over Katchoo on a field assignment as she was actually an accountant who was bored in the company.