Miiko Takeshita hails from the technologically inventive Takeshita Group family. She sports short, middle-parted blonde hair, bright green eyes, and a distinctive small ahoge. Her signature accessory is light pink headphones adorned with white ribbons, and she is the shortest member of her group.

Her personality is unfailingly cheerful and playful, where fun reigns supreme. Miiko forms connections effortlessly and holds deep care for her fellow group members. While her thought processes can appear obscure, this stems more from spontaneous action than overanalysis. She finds paranormal mysteries, horror movies, and haunted houses entertaining rather than scary, but actively avoids sad stories.

Miiko speaks exclusively in third person, calling herself "Miiko" and frequently ending sentences with "なの〜" (nano). Extensive international travel with her father, enabled by her family's resources, fueled her dream of making friends worldwide. These journeys facilitated her learning of English, Chinese, Spanish, French, Russian, Malay, Arabic, and Portuguese, plus Morse code. Though conversationally fluent in English, she struggles academically with its grammar.

She demonstrates adaptability through various collaboration events, where her character design reinterpreted figures such as Shirakami Fubuki, Mitsukai Dokuro, Dejiko, Hachikuji Mayoi, Azusagawa Kaede, Minato Tomoka, and Ookawamura Mei. In one storyline, she adopted the epithet "Wicked Angel Miiko." Miiko is also noted within her franchise's game as the sole character to indirectly break the fourth wall.

Her approach to performances and interactions consistently emphasizes joy and connection, reflecting her core belief that enjoyment supersedes all else.