Shuuhei is someone who appears to be calm and mature despite having a punk-like appearance. He tends to take responsibility and avoid violence when possible, which aligns with his virtuous character as depicted in the image of his Captain. However, later revelations showed that his Captain was actually a traitor. Despite this, Shuuhei is often seen with Renji and Kira during their academy days, following them as senpai. Omake chapters also suggest that he has a perverted side.
While little information is available about Shuuheis abilities, it's known that even in the academy, he was quite skilled and commonly led other shinigami trainees on mock missions. Despite failing the entrance exam twice, his talent allowed him to become a seated officer in the Gotei 13 without further testing. He only released his Zanpakuto during his battle with Findor Carias, an Arrancar from Barragons Fraccion. When the Arrancar revealed his Resureccion as Pinsa Guda, Shuuhei released his own Zanpakuto named Kazeshini with the command "Reap." Its sealed form is a katana with an octagonal tsuba.
Hes also shown as a child in the Pendulum Arc. This is when he first met Mugurama Kensei who saved him from a Hollow. Shuuhei was then inspired by Kensei, thus adding the 69 tattoo to his face to match the one on Kenseis stomach.