She made her debut in Gabe Goes to School when Lillie brought her new friends home and she came running out with Lillie's Vulpix and Lillie's mother and older brother. Team Rocket arrived and attempted to steal Vulpix and Lillipup, but accidentally captured Lillie and decided to take Lillie instead which angered her mother who fought to save her daughter and Lillie was reunited with Vulpix and Lillipup. Gabe then had Pik send Team Rocket blasting off. Lillie then asked Lillipup and Vulpix to join her on her traveling journey and they agreed to.
Like Lillie's Vulpix, Lillipup is caring and loyal towards her trainer