Kay is the eldest daughter of Sam and Grace Bennett, and older sister to Jessica. Kay has been in love with Miguel Lopez-Fitzgerald for most of her life, and was devastated when he met her cousin Charity.
She spent years scheming to steal him away for herself. She even enlisted the forces of darkness on multiple occasions to help her achieve her goal, including teaming up with Hecuba and creating a Zombie version of her rival.
She was eventually able to use evil to trick Miguel into making love to her and getting her pregnant, resulting in the birth of their baby daughter Maria. After she had a falling out with her mother, she moved into Tabitha's house and began dating Fox Crane, eventually marrying him.
Upon Miguel's return to Harmony after spending two years searching for Charity, Kay learned about Fox's misdeeds and finally has the chance to be together with Miguel.