She is a Japanese writer who is best-known for being the author of the manga and anime series Candy Candy. Writing under the name, Kyoko Mizuki, she has won Kodansha Manga Award for Best Shoujo Manga for Candy Candy in 1977 with Yumiko Igarashi.

Under the name, Keiko Nagita, she won the Japan Juvenile Writers Association Prize for Rainette, Kin Iro no Ringo (Rainette - The Golden Apples) in 2007.

Her short story Akai Mi Hajiketa is printed in Japanese Primary School Textbook for 6th grade (Mitsumura Tosho Publishing Co.,Ltd.).

Her picture books Shampoo Ouji series was adapted into anime television series in October 2007.