Kimura was born in Tokyo and graduated from Tama Art University. After working in arts education and as the creative director behind children's television programming, Kimura moved over to writing picture books and stories.

With his book, Arashi no Yoru ni (One Stormy Night), Kimura received The Kodansha Award for Picture Books, and the JR Award for Children's Books & Publications - Junior Category. Kimura adapted this same work as a stage play, and also received several awards. In 2005, the animated film adaptation of "One Stormy Night" won the Japan Academy Award in its category. With up to 500 literary works to his credit, many of them are long-time bestsellers. Other notable works include "Wings of Flight", and "Hungry Diary of Gonnosuke, the Wolf".