Mika Yuitsuka is a former figure skater and the older sister of the protagonist Inori Yuitsuka in the anime Medalist. She is eight years older than Inori and serves as the initial inspiration for Inori's dream of becoming a figure skater. Mika began skating because her mother Nozomi wanted her to try various activities, and after sampling different pursuits, figure skating became the one that stuck. She trained at the Meijō Crown Figure Skating Club, and during her time as a novice skater in the B division, she achieved notable success, winning the Chubu block competition. However, her skating career was cut short by a bone fracture, which led her to give up the sport.

Personality-wise, Mika is described as energetic and bright, with an overflowing sense of vitality. From childhood, she was widely perceived as someone who was good at everything she attempted, and people around her often saw her as a cute, cheerful girl with a natural ability to excel. She genuinely loved figure skating, but her devotion to her family ultimately proved even stronger than her love for the sport. This deep family loyalty is a defining trait: her bond with her younger sister Inori is especially significant, as Mika's own past as a skater planted the seed of aspiration in Inori that later blossoms into a full commitment to competitive skating.

Mika currently lives abroad in Canada, where she is a university student. In addition to her studies, she works as a magazine model. Despite being physically distant from her family, she remains an emotional anchor for Inori. Within the narrative, Mika functions as the root of Inori's dream, a source of emotional support, and a link to the past of figure skating within the Yuitsuka family. Her earlier achievements and her later decision to step away from the ice create a backdrop of both possibility and loss that informs Inori's own journey. Through her relationship with Inori, Mika helps bridge the audience's understanding of the sport, showing both its early rewards and the difficult choices it can demand. Her character does not undergo a dramatic transformation over the course of the story so much as she stands as a fixed point of inspiration and familial love, watching and supporting from afar as her sister pursues the path she herself once walked. Her notable abilities include her past technical skill as a skater, her bright social energy, and her capacity to balance life as a student, model, and supportive older sibling across international borders.