Sakura Karasuma teaches English at the high school attended by the main characters, often seen wearing a tracksuit jersey. She embodies a kind, meek, and somewhat absent-minded personality.

Initially perceived by student Alice Cartelet as a rival for Shinobu Omiya's affections due to Shinobu's admiration, Sakura gradually earns Alice's fondness. She consistently supports the students, frequently helping resolve friendship disputes.

Sakura has two older brothers. She spends significant time with fellow teacher Akari Kuzehashi, acting as her mentor; Kuzehashi regularly seeks Sakura's advice on professional and personal matters, highlighting Sakura's role as a trusted colleague.

Her relationships include elements of lighthearted, friendly rivalry, particularly concerning Shinobu's attention. Throughout the series and the film "Thank You!!", which follows the students' senior trip to Nara and Kyoto and their impending graduation, Sakura provides stable guidance to both students and colleagues, offering gentle support as they navigate transitions.