Noa Shiragiku is a serious-minded kyudo practitioner at Kazemai High School, distinguished by her long black hair styled in a hime cut. She approaches archery with intense dedication, often reprimanding male teammates for perceived frivolity. Noa maintains privacy regarding personal challenges, exemplified by concealing an illness before a competition to prevent concern. Her profound emotional connection to kyudo manifests visibly when deeply moved, such as her tearful, flushed reaction to the sound of Minato Narumiya's arrow release and flight.

Raised in a traditional Japanese household, she cultivated interests in calligraphy and traditional arts. Within the kyudo club, she volunteered alongside Yuuna Hanazawa for the prefectural tournament when advisor Tomio Morioka proposed it. Despite her kyudo experience, this marked her first competition. Noa demonstrates fierce loyalty, openly defending captain Rika Seo's feelings against insensitive remarks.

She shares a strong bond with fellow female archers Yuuna Hanazawa and Rika Seo, expressing deep respect for Rika's leadership. Her relationship with Minato Narumiya centers on significant admiration for his archery skill, though the precise nature of her feelings remains undefined beyond this appreciation. Her name "Shiragiku" combines "white" and "chrysanthemum," while "Noa" incorporates characters meaning "from" and "love/affection."