[4] In 2002, at the age of 13, Michishige participated in the Love Audition 2002 held by Up-Front Agency in search of new members for the Japanese female idol group Morning Musume.

Michishige, along with Eri Kamei, Miki Fujimoto, and Reina Tanaka were admitted to Morning Musume as sixth-generation members on January 19, 2003.

On July 16, 2003, the sixth-generation members (with the exception of Miki Fujimoto) released their first photobook and corresponding DVD, both shot in Hawaii, as part of the Alo Hello!

Towards the end of 2003, Michishige began appearing in the show Revelations of M (Mの黙示録, M no Mokushiroku), as a regular with ex-Morning Musume member Yuko Nakazawa.

During the summer, Michishige appeared in her first solo photobook and was placed in a temporary unit called Ecomoni with fourth-generation Morning Musume member Rika Ishikawa.

Originally, the goal of the group was to promote environmental awareness only for the duration of the Cool Down the Hot Earth (熱っちぃ地球を冷ますんだ, "Atchii Chikyū wo Samasunda") festival, but their popularity led to the members being cast as voice actors for the fourth Hamtaro movie—along with Hello!

Project soloist Aya Matsuura, with whom they also released the main theme for the film, titled "Tensai!

That year, she was assigned to be a mentor to seventh-generation member Koharu Kusumi, with whom she formed a duo called Rainbow Pink in the beginning of 2006.

Running approximately 30 minutes per episode, Michishige's show consisted of her answering fan mail and participating in several games, among which saying a given phrase/expression in reverse, and giving general advice to her listeners.

[5] Michishige also starred in Bow30° (「おじぎ30度」), an original internet drama created for the purpose of advertising the Family Restaurant chain Gusto (ガスト), as Ruruka Chī (地井ルルカ), a novice waitress training under the supervision of her seniors Karin Kinoshita (木下花梨) (played by Morning Musume's Ai Takahashi) and Mika Mochizuki (望月深華) (Reiko Tokita).

On June 9, 2007, Michishige began co-hosting the Young Town radio show as a result of Miki Fujimoto's Friday magazine scandal and subsequent resignation from Morning Musume.

With her exit announced for Morning Musume's Fall 2014 concert tour, the group consisted only of the three most recent generations since the introduction of the fourth-generation members in 2000.

In December 2023, Michishige's agency announced she had recently been diagnosed with obsessive–compulsive disorder and would be restricting some activities until her symptoms improved.