Mami Misato is a petite brown-haired student at Takizawa High School, classmates with the protagonist Yamada. She typically wears her hair in twin buns and has brown eyes. Academically, she struggles significantly, frequently failing tests; her lack of focus frustrates her teachers. Her defining trait is an intense obsession with boys she finds attractive. This manifests as hyperactive energy, driving her to aggressively pursue romantic targets once fixated. She possesses a noted "sixth sense" for detecting attractive males but is generally perceived as clingy or annoying by her peers.

Her romantic pursuits form a core part of her storyline. She becomes infatuated with wealthy student Keiichi Kanejo, stalking him by photographing him at the airport, selecting him as a "hot guy" during a school scavenger hunt, attempting to seduce him at a Christmas party, and trespassing onto his family estate. Later, her interest shifts to the effeminate-looking Kawai Mizuki, prompting a brief makeover to adopt a more mature appearance aimed at appealing to him.

Mami Misato's understanding of romance and relationships is heavily driven by shoujo manga, which she treats as instructional guides. This often results in impractical or exaggerated advice, though characters like Yamada occasionally relate to it. She maintains a close friendship with Aoi Katase, forming a dynamic duo where Mami's exuberance contrasts with Aoi's demeanor. Throughout the series, she functions primarily as comic relief through her persistent, unsuccessful romantic endeavors and exaggerated reactions to setbacks.