Shuichiro is a tall and handsome lightly tan-skinned man with dark brown hair that has bangs swept to the left side, dark brown eyes and he has a mole under his left eye resembling his niece Momoe Sawaki. He wears a brooch on his collar with a figure resembling a bird on it.
Shuichiro appears to be a kind and soft spoken man with a passion for art who seems to enjoy interacting with his students and wants to see them succeed in life. He is rather polite and has some mannerisms. At one point, he is seen sketching Ai Ohto for a planned painting and he tells her to have more confidence.
Shuichiro often visits Ai Ohto's home to see how she is doing. He says he does not mind that because her house is on his way home.
In a flashback, Koito Nagase is shown crying into his chest in an empty classroom. Ai walks in on this, apologizes for interrupting, and runs away. This may be hinting that Sawaki and Koito had an inappropriate relationship.
One evening, Shuichiro visits the Ohto home for dinner. During dinner, Shuichiro and Tae Ohto announce to Ai that they would like to begin dating, but they do not want to do anything that would make her uncomfortable. Ai, who seems surprised and disturbed at the revelation, tells them to do whatever they want and that it is none of her business.
As she told to the other girls, Rika Kawai suspects Shuichiro to be somehow responsible for Koito's death. For now, this remains a theory, as she does not have any evidence to backup the claim. Momoe Sawaki is quite upset to hear these suspicions, explaining that she knows her uncle would never hurt anyone.
Shuichiro hopes to make a living as a painter, and he hosts a solo art exhibition after a painting of his wins an award. He invites Ai to the event, and when she arrives she discovers the painting that won the award was the one Shuichiro painted of her. Shuichiro tells Ai that the painting depicts her grown up, and he says that she will grow up to be a wonderful woman like her mother. Shuichiro reaffirms his love for Tae, and once again encourages Ai, telling her that she should have faith in herself. Ai begins to cry at these statements, but she recomposes herself. She then firmly asks Shuichiro for the reason behind Koito's death.
- The name Shuichiro means "discipline, study, conduct oneself well, master" (修) (shu), "first (一) (ichi) and "son" (郎) (ro).
- Shuichiro's surname Sawaki means "marsh" (沢) (sawa) and "tree, wood" (木) (ki).