|Anime debut||Yu-Gi-Oh! (Toei) episode 16: "Breadth's Change - Crisis of the White Robe"|
Shizuka is the brother of Katsuya Jonouchi. Following their parents separation, Shizuka lived with their mother, while Katsuya lived with their father. Shizuka is ill, spending a lot of time in the hospital.
Unlike the manga, she uses the same surname as her brother, rather than her mother's maiden name.
Katsuya Jonouchi kept details of his sister secret from his friends. However Yugi spotted him buying a large teddy bear for her birthday. The teddy got damaged when Katsuya protected Yugi in a fight, so he got Yugi to come with him to the hospital and help perform a comedy act for her. Katsuya apologized for not having a present, but Shizuka insisted it was okay. Their mother was running late and she was happy to have his company. Shizuka noticed Katsuya's injuries from his fight, but he insisted it was nothing. Nurse Miyuki Sakurai treated Katsuya's wounds and advised him to stay out of fights, so as not to worry Shizuka.
Shizuka learned that Miyuki had been fired by Dr. Kekeru Goyu, for putting a patient in danger after forgetting to follow orders. However she did not believe that rationale and told Katsuya what had happened. Katsuya suspected it was due to Miyuki rejecting Goyu's romantic advances and complaining about his neglect of patients. He threatened to expose Goyu, but backed down when Goyu said it would still be in his power to have Shizuka removed from the hospital.
Worried about how Katsuya was feeling, Yugi thought he should spend time with his friends, so he brought Hiroto Honda, Anzu Mazaki and Miho Nosaka to visit Shizuka at the hospital. They surprised Katsuya when he arrived with cake for Shizuka.