Gō Matsuoka serves as the manager of the Iwatobi Swim Club while attending Iwatobi High School, distinct from her older brother Rin who attends rival Samezuka Academy. She leverages her connection to Rin to organize joint swim practices and training sessions between the schools. Her responsibilities include providing logistical support for competitions and team activities. Gō exhibits a notable interest in male musculature, frequently experiencing nosebleeds when observing shirtless swimmers during meets. Despite this tendency, she performs her managerial duties seriously, focusing on operational tasks and the team's needs. Her attire includes her school uniform, a yellow shirt with jeans (sometimes layered with a team jacket), a swimsuit, waitress attire, a pirate costume, Arabian-inspired clothing, and traditional miko robes used during speeches. Beyond her brother, Gō interacts with several characters. She receives persistent attention from former Samezuka captain Seijūrō Mikoshiba, while his younger brother Momotarō Mikoshiba develops a crush on her. Within the Iwatobi club, she coordinates with members Haruka Nanase, Makoto Tachibana, Nagisa Hazuki, and Rei Ryūgazaki. On one occasion, she and the club advisor left the male members camping overnight on a beach while they stayed in a hotel.