Seishun Gakuen 3rd Year Class 2
Birthday: 30th April (Taurus)
Height: 175cm
Weight: 55kg
Blood Type: O
Dominant Hand: Right
Play Style: Counter-puncher
Shoes: NIKE(NIKE READY AIR ZOOM STERLING)
Racket: WIMBLEDON(Tour Merit)
Special Move: Moon Volley
Favorite food: Shish Kebabs, Clam Soup, Pears
Hobbies: keeping fish, swimming
Family: father, mother, younger sister
Father's occupation: Tax officer
Favorite subject: English
Favorite color: White
Preferred type: Girls who look good with glasses

Oishi is the vice-captain of Seigaku Tennis team. He is a worry-wart and is much concerned with other people's welfare, thus erning the nickname "Seigaku's mom." He plays doubles with Eiji Kikumaru and their tandem is called the Golden Pair.