Mitsuhiko Tsuburaya is a first-grade student at Teitan Elementary School and a core member of the Detective Boys, the amateur detective group he helped form alongside his classmates Ayumi Yoshida, Genta Kojima, and Conan Edogawa. He comes from a household of educators; both of his parents are teachers, and he has an older sister, Asami, who is about ten years his senior. This upbringing has instilled in him a notably formal and polite manner of speaking, especially toward elders, and a strong sense of responsibility and punctuality.

Intellectually, Mitsuhiko is the most bookish and scientifically inclined of the Detective Boys. He enjoys reading science books, studying history, and learning about a wide range of subjects for his own pleasure. He approaches problems with a logical, methodical mindset and often acts as the group's strategist when Conan or Ai Haibara are unavailable. He is proactive and thinks ahead, frequently bringing useful tools or taking notes during investigations, which has proven valuable in solving cases. Despite his advanced thinking for his age, he still delights in age‑appropriate activities such as treasure hunting, making snowmen, and watching monster movies or the Kamen Yaiba series. He has a mild dislike for carrots, which he will avoid eating if possible.

Mitsuhiko's motivations are driven by curiosity and a genuine desire to help others. He takes pride in his knowledge and is happy when it proves useful, feeling rewarded when his research pays off during an investigation. He is also deeply loyal to his friends, particularly Ayumi and Ai, toward whom he harbors romantic feelings. The story has shown him torn between these affections, and he has gone to great lengths to please them, such as venturing alone into a forest to catch fireflies for them.

In the events of Detective Conan: One‑eyed Flashback, Mitsuhiko plays a supporting role alongside the other Detective Boys. During the investigation in the Nagano mountains, he, Genta, and Ran Mouri assist the police by helping to drive off an attacker who ambushes Detectives Yui Uehara and Kansuke Yamato. His quick thinking and willingness to act under pressure contribute to the team's efforts to protect the officers and advance the case.

Key relationships define his character. He is close friends with Genta and Ayumi, having known them since preschool or kindergarten, and he shares a friendly but sometimes competitive dynamic with Conan. He respects Ai Haibara and has shown a protective side toward her, once carrying her to safety after she sprained her ankle and later saving her from a fall during a high‑risk situation. Mitsuhiko also maintains respectful relationships with the adult detectives and Professor Hiroshi Agasa, always addressing them with formal honorifics.

Over the course of the series and into the movie, Mitsuhiko demonstrates steady development. He becomes more confident in his deductive abilities and often takes the lead when the older, more experienced members of the group are absent. His notable abilities include a broad general knowledge, the capacity to analyze puzzles and codes, and a talent for preparation and note‑keeping. He is also resourceful in practical situations, such as applying first aid or using the Detective Boys’ gadgets effectively.

Overall, Mitsuhiko Tsuburaya stands out as an intelligent, earnest, and courteous young boy whose growth as a junior detective and as a friend continues to be a consistent part of his role in the Detective Conan story.