The group was formed as a rock band in 2018, with their first single "Hoshie" being released the same year; the title track was used as the ending theme to the anime series Sirius the Jaeger.

The name Sajou no Hana was coined by Kitani, who was inspired by Sana's image and singing style, with the name using Latin characters instead of using Japanese text with meanings as a way to prevent others from developing bias when listening to their music.

"Aoarashi no Ato de" was used as the ending theme to the anime series A Certain Scientific Railgun T,[9] with its B-side track "Koko ni Itai" (ここにいたい) being used as an insert song to the show's fifteenth episode.

[11] The group released the single "Tentō" (天灯) in 2022, with the title track being used as the opening theme to the first cour of the fourth season of Is It Wrong to Try to Pick Up Girls in a Dungeon?.

[13] Later that year, it was announced that Watanabe and Kitani were leaving the band in 2024 and the group would be reorganized as a music unit focused on Sana, although they would continue to be involved in the project in a supporting capacity.