Yuuichi is a member of the Fuuka Academy Student Council. He first appears in Episode One on the same ferry that Mai Tokiha is taking and the two quickly form bad impressions of each other. Shiho Munakata calls him her older brother even though they are not related by blood. He works with the Student Council doing odd jobs for them (prompting Mai to label him a "lackey") and sits next to Mai in class.
Yuuichi used to be a member of the Fuuka kendo club and regularly made it into the nationals until he was suffered a severe injury to his knee at some point in the past, though the exact circumstances and nature of the injury are never explained in the anime. Masashi Takeda of the kendo club is seen looking sadly at Yuuichi's name card on the wall of the kendo dojo at one point during the anime. Disenchanted, after his injury Yuuchi became a feared delinquent, but Shiho manages to convince him give up his antisocial ways.