Mitsuhiko Tsuburaya is a first-grade student at Teitan Elementary School and a founding member of the Detective Boys. He lives with his parents, both school teachers, and has an older sister named Asami Tsuburaya, who is approximately ten years his senior. His parents' professions contribute to his strict and formal upbringing, which emphasizes polite speech and respect for elders. He exhibits a scientific and analytical approach to problem-solving, relying on his extensive reading of science books and general knowledge. He believes technology can resolve most issues and frequently prepares for various scenarios by studying historical, scientific, and general subjects. This preparedness allows him to contribute useful insights during investigations, such as providing precise historical facts or taking detailed notes in his Detective Boys notebook to preserve critical information. He is characterized by his formal demeanor, often addressing elders with the respectful suffix "-san" regardless of their relationship. Despite his intelligence and maturity, he retains typical childhood interests, such as treasure hunting, building snowmen, and participating in group activities with his friends. He dislikes carrots and typically avoids eating them when possible. Mitsuhiko developed romantic feelings for both Ayumi Yoshida and Ai Haibara, struggling with his equal affection for them. He once sought advice from Ran Mouri about whether having feelings for both girls made him a bad person. His dedication to his friends is evident in episodes such as when he ventured into a forest to catch fireflies for Ayumi and Haibara after hearing them admire the insects' beauty. During this adventure, he was captured by the escaped serial killer Ki'ichiro Numabuchi, who spared him due to their shared appreciation for fireflies. Throughout various cases, Mitsuhiko has demonstrated leadership and quick thinking, especially when Conan Edogawa or Haibara are absent. He deciphered a riddle to find an exit from a cavern after Conan fainted. In another instance, he assisted Haibara by creating a bandage for her sprained ankle using a method taught by Conan and carrying her to safety, leaving a coded message to alert the other Detective Boys of their location. In the film "Countdown to Heaven," Mitsuhiko played a critical role in saving Haibara by preventing her fall from a moving vehicle, declaring he would never let her go. He also confided in Ran about his conflicting emotions toward Ayumi and Haibara. His parents' emphasis on politeness and formal speech is consistently reflected in his behavior. He maintains formal relationships with adults and peers, often using honorifics such as "-san" for figures like Ran Mouri, Professor Agasa, and members of law enforcement. His interactions with fellow Detective Boys, including Conan Edogawa, Genta Kojima, and Ayumi Yoshida, are collaborative and supportive.