Satsuki Suzuki is a first-year tuba player in Kitauji High School's concert band. She possesses a short stature, fair skin, and emerald green eyes. Her gold blonde hair is styled in two side ponytails with straight bangs across her forehead, each ponytail decorated with a green pearl. She attended Higashi Middle School with Hazuki Katou and shares an elementary school background with Mirei Suzuki, though they are not related despite the shared surname.

Satsuki exhibits a friendly, cheerful, and sociable personality, reminiscent of traits seen in Hazuki Katou and Sapphire Kawashima. She forms connections readily and demonstrates persistent efforts to build relationships, particularly with the reserved Mirei Suzuki. During the Sunrise Festival preparations, Mirei temporarily left the band due to frustration over Satsuki and Hazuki's lighthearted behavior, highlighting Satsuki's initial unsuccessful attempts to connect. Mirei later rejoined after Kumiko Oumae intervened.

Her personal preferences include enjoying her mother's curry rice but disliking eating cup ramen alone. She has no favorite color. Her hobbies are playing with dogs and searching for interesting things. A noted talent is her ability to separate trash with precision.

Within the concert band's bass section, Satsuki plays alongside fellow first-year students Kanade Hisaishi (euphonium), Mirei Suzuki (tuba), and Motomu Tsukinaga (double bass). She navigates the challenges of integrating into the ensemble under the mentorship of second-year Kumiko Oumae and third-year Tomoe Kabe.