Miwa voiced protagonist Mitsuo/Perman No. 1 in the 1967 television anime adaptation of Fujiko Fujio’s Perman manga, and continued to voice the character in later subsequent anime adaptations.
She voiced the titular Unico in Madhouse’s 1981 anime film The Fantastic Adventures of Unico, as well as in the later Unico in the Island of Magic film.
She later voiced Hirame Hirayama in Isao Takahata’s Chie the Brat television anime.
She voiced protagonist Wonder-kun in Mushi Production’s Space Journey – The First Dream of Wonder-kun anime special.