Juna Shiratori is a former competitive figure skater and a key supporting character in Medalist. Known for his striking appearance with white hair and pink eyes, he currently works as a professional choreographer and has also gained fame as a TV personality and commercial celebrity. His background is deeply rooted in a prestigious skating club in Niigata, where he was a clubmate and contemporary of Tsukasa Akeuraji and Kohei Kamogawa, also training alongside the talented ice dancer Hitomi Takamine.

In his youth, Juna harbored a powerful ambition to become an Olympic athlete. However, he came to realize that his natural talents were better suited for performance and entertainment rather than competitive success. This self-awareness led him to pivot away from being a competitive singles skater, leveraging his skills to become a celebrated choreographer and a beloved, if somewhat eccentric, public figure.

Juna's personality is large, theatrical, and often overwhelming. He is energetic, clownish, and slightly self-absorbed, with a notorious habit of picking on others in ways that can come across as insensitive. His humor is a primary mode of interaction, frequently manifesting in elaborate pranks; a memorable example involves him wearing a duck costume and playfully biting Tsukasa on the head, a stunt that elicits a fierce protective reaction from Tsukasa's student, Inori Yuitsuka. This lack of awareness regarding social cues often baffles or irritates his more serious former clubmates, Tsukasa and Kohei, leading to a dynamic where his attempts at comedy are not always appreciated. Despite this, his vibrant energy provides much of the series' comedic relief, and his interactions with the stoic Kohei feel like a familiar bickering between two old friends.

Within the story, Juna occupies a vital role as the choreographer for Miku Ahiru, a gifted young skater coached by Kohei at their former home rink. His professional expertise is his primary contribution to the world of competitive skating. He is responsible for designing Miku's programs, and he is confident enough in his technical knowledge to offer opinions on a skater's readiness for difficult jumps, though his suggestions are sometimes playfully dismissed by the more methodical Kohei. His relationship with Miku is that of a supportive, if quirky, mentor who is deeply invested in her success, working as part of a dedicated trio alongside Kohei to help her achieve her goals. His key relationships are defined by this past and present connection to his skating club: a history of shared struggle with Tsukasa and an ongoing, argumentative yet loyal partnership with Kohei.

Juna's character development is reflected in his acceptance of his own strengths. While he once dreamed of Olympic glory as a skater, he has forged a successful career by channeling his love for the sport into artistic expression and public performance. He was once eager to act as a senior and coach to Tsukasa when the latter first joined the club, though that attempt resulted in an exhausting, forced comedic dynamic for both of them. Mature and established in his current path, he has found a way to remain an integral part of the figure skating world, using his talents to guide the next generation of skaters like Miku while enjoying the spotlight as a celebrity. His notable abilities lie not in competitive results but in his exceptional skill for choreography, his flair for entertainment, and his ability to create memorable, if chaotic, moments both on and off the ice.