She made her acting debut in the same year, starring as Shiori Uchiura / Little Girl in the kaiju film Rebirth of Mothra II.

[1] Since then, Mitsushima has had starring roles in numerous films and television dramas including 2010's Sawako Decides, written and directed by Yuya Ishii.

In 2017, she provided lead vocals for fictional band Doughnuts Hole's "Otona no Okite", the theme song for television drama Quartet, in which she starred as Suzume Sebuki.

In the same year, she appeared as a featured vocalist in Mondo Grosso's song "Labyrinth" and starred as a dancer in the music video (over 35 million views on YouTube, as of February 2023[update]).

[5] Mitsushima announced via fax through her agency that she has registered her marriage with film director Yuya Ishii on October 25 2010,[6] they later divorced in early 2016.