Makoto Tsukimoto
Smile is a member of the Katase High table tennis club, along with his best friend Peco. Unlike the other members of the club, Smile thinks of the sport as a job or a way to pass time. He does not try to enjoy it for fun and often lets less able players beat him out of consideration for their feelings. The other members of the club ironically nicknamed him Smile because he never does.
It is later revealed that the name stems from the first time he smiled after winning a junior table tennis tournament with his childhood friends.