[5] At the age of 10, she was selected as the youngest ever Grand Prix winner out of 44,120 applicants[6][7] and became a member of Toho Entertainment's Cinderella Room along with Mone, who won the Judges' Special Award.

[11] Kamishiraishi made her CD debut in June 2015 with the theme song "Su-ma-i-ru" ("Smile") for the NHK Educational TV animated series Hanakappa [ja].

[12] Two years later, she sang the theme song "Narratage" for the film of the same title [ja], written and composed by Yojiro Noda of Radwimps, under the stage name "Adieu".

[20] Kamishiraishi appeared in a series of commercials for Kirin Company's Gogo no Kocha bottled tea, titled Aitai tte, Atatametaida (あいたいって、あたためたいだ, "I Want to See You and Get Warm"), from 2016 until 2018.

The series featured her character covering popular songs, such as "Yasashii Kimochi" by Chara,[21] "Kabutomushi" by Aiko, "Kaede" by Spitz,[22][23] and "366 nichi" by HY.

[30] Director Mamoru Hosoda later directed the new title sequence of the Nippon TV program Friday Road Show!, with the concept of a girl who is visiting a salon in a foreign country and Kamishiraishi performing its theme song "Era".

[35] In addition to practicing swimming for the role, she underwent physical transformation to an athlete's body shape by gaining 7 kg in weight.

[44][13] In August 2021, Kamishiraishi portrayed Minami Sakuda in the film One Summer Story, adapted from the manga Kodomo wa Wakatte Agenai [ja] by Retto Tajima.

[38] Kamishiraishi appeared in her first starring role in a television drama in Solomon's Perjury (2021), broadcast on Wowow, the same station where she made her acting debut nine years prior.

In 2018, she enrolled in Meiji Gakuin University, where she majored in humanities and studied art theory, sociology, and photography history;[4][5][33] she graduated in March 2023.

Around the third year of junior high school, she became interested in analog cameras and was taught by Yuina Kuroshima, with whom she co-starred in the dramas Goodbye, Debussy and Chimudondon.