is a Japanese singer, model, and actress. She is a member of the girl group Hinatazaka46 (formerly Hiragana Keyakizaka46) and an exclusive model for the fashion magazine Non-no.
Kosaka has held the lead performer position for the most singles in Hinatazaka46 with eight singles, earning her the moniker "Absolute Ace". Prior to signing with Non-no in 2025, she was an exclusive model for Seventeen magazine from 2018 to 2024. She has appeared in the feature films The Japanese Doll (2019) and Jump!! The Heroes Behind the Gold (2021), and the drama series Dear Radiance (2024) and Strobe Edge (started 2025). She has also served as a brand ambassador for Sony Assurance since 2022 and hosted the radio program Sony Assurance Quest for the Future on J-Wave since 2023.
Career In August 2017, Kosaka passed the auditions for new members of Keyakizaka46's subgroup Hiragana Keyakizaka46 and entered the group as a second-generation member. She made her debut in the song "No War in the Future", released on the Keyakizaka46 single "Kaze ni Fukarete mo".
On May 19, 2018, Kosaka made her runway debut at the GirlsAward 2018 Spring/Summer show in May 2018. Seventeen announced two days later that she would be one of the magazine's exclusive models, making her the first Hiragana Keyakizaka46 member to become an exclusive model.
Hiragana Keyakizaka46 was renamed to Hinatazaka46 in February 2019. Kosaka held the center (lead performer) position for the title song of their debut single, "Kyun", and subsequent three singles. She has held the center position for the most singles in the group with eight singles, earning her the moniker .
After appearing in the group's television dramas Re:Mind (2017) and Dasada (2020), Kosaka made her silver screen debut as the main character of the 2019 mystery film . She also appeared in Jump!! The Heroes Behind the Gold, a 2021 film about ski jumping at the 1998 Winter Olympics, in which her character was based on ski jumper ; Hominis commented that despite performing alongside more experienced cast members, she maintained a unique presence by acting "from the heart".
Kosaka's solo photobook, titled Kimi wa Dare?, published by Seventeen publisher Shueisha and produced by the Seventeen magazine editorial staff, was released on June 29, 2021. In an interview, she remarked that she had always wished to release a photobook in her teenage years and that the book was a "memory album" of her youth. The book topped the Oricon 2021 photobook sales chart with 166,876 copies sold. As a dinosaur enthusiast, she was also appointed as an ambassador for Sony's DinoScience exhibition, which would be held from July to September at the Pacifico Yokohama. However, she went into hiatus on June 26 for health reasons and did not participate in the rest of the event; she also did not take part in Hinatazaka46's sixth single, "Tteka". Her radio program, on Tokyo FM, was taken over by fellow member Mirei Sasaki and later renamed to .
Kosaka announced her resumption of activities on March 4, 2022, and made her comeback on March 30 in the third Hinatansai anniversary concert, Hinatazaka46's long-awaited first performance at the Tokyo Dome. She also returned to the center position for "Boku Nanka", despite her "mixed feelings" about the appointment.
In a late 2021 survey by , Kosaka was ranked the seventh most popular teen actress in Japan (under 20 years old as of February 2022) based on public recognition and interest. Despite that, Kosaka did not appear in any acting work since returning from hiatus until 2024, when she joined the cast for the taiga drama Dear Radiance as Heian-era poet Sai'in no Chūjō, and appeared as supporting character Rin Arikawa in the feature film All of Tokyo!, starring the Hinatazaka46 fourth-generation members. In 2025, she appeared in the drama adaptation of Strobe Edge, which ran for two seasons.
Since 2022, Kosaka has served as a brand ambassador for , appearing in various television commercial campaigns for its auto insurance product line. These include solo spots and series alongside actresses Yuki Uchida and Asuka Saitō, as well as those featuring fellow Hinatazaka46 members Hinano Kamimura in 2024 and Kaho Fujishima and Yōko Shōgenji in 2025. Additionally, Kosaka provided her voice for the company's Good Drive mobile application and has hosted the radio program Sony Assurance Quest for the Future on J-Wave since 2023.
Kosaka, along with Miku Kanemura and Yōko Shōgenji, was a subject of the Triangle Magazine 02 photo collection, or "visual magazine", published by Kodansha on January 23, 2024. Among the three models, she represented the theme "reunion". It placed first on both the Oricon Book and Photobook weekly rankings of its release week with 61 thousand copies sold.
In November 2024, Kosaka ended her exclusive modelling contract with Seventeen after 6.5 years, expressing her wish to be seen more as an adult woman and an idol. On March 7, 2025, the fashion magazine Non-no announced that she would be one of its exclusive models. She graced the magazine's cover for the first time on its April 2026 issue.
Kosaka made her voice acting debut together with Kaho Fujishima in the animated feature film That Time I Got Reincarnated as a Slime the Movie: Tears of the Azure Sea, released on February 27, 2026.
Personal life Kosaka played volleyball in middle school and occasionally demonstrates her skill in her appearances. She has an older brother who is a Keyakizaka46 fan.
Kosaka's main interests include dinosaurs and reptiles. She also enjoys comedy shows and named Kazuya Kojima of Unjash and Audrey as her favorite comedians.
Discography Kosaka has participated in all of Hinatazaka46's singles and albums except "Tteka" (2021). As of February 2026, she has been the original center (lead performer) of the most title songs in the group with eight songs: "Kyun", "Do Re Mi Sol La Si Do", and "Konna ni Suki ni Natchatte Ii no?" in 2019; "Sonna Koto Nai yo" in 2020; "Boku Nanka" in 2022; and "Sotsugyō Shashin Dake ga Shitteru", "Love Yourself!", and "Onegai Bach!" in 2025. Other notable songs include:
"Kirei ni Naritai" (Hashiridasu Shunkan, 2018), as a trio with Akari Nibu and Miho Watanabe "Footsteps" ("Kyun" B-side, 2019), performed by all of the group's exclusive magazine models at the time "See Through" (Hinatazaka, 2020), duet with Miku Kanemura ("NaoMiku") "Sekai ni wa Thank You! ga Afureteiru" ("Kimi Shika Katan" B-side, 2021), center, second generation members song "Mou Konna ni Suki ni Narenai" ("Boku Nanka" B-side, 2022), performed by all members born in 2002 at the time (Kosaka, Miku Kanemura, and Hiyori Hamagishi)
Collaborations "Hatsukoi Door" (AKB48 single "Jiwaru Days" B-side, 2019), Sakamichi Series collaboration with the AKB48 Group (SakamichiAKB) by BocchiBoromaru, The Elusive Samurai second ending song (2026), featured artist with Yōko Shōgenji and Kaho Fujishima
Filmography
Film YearTitleRoleNotes2019The Japanese DollYuri HiraiLead role2021Jump!! The Heroes Behind the GoldYoshiko Kobayashi2024All of Tokyo!Rin Arikawa2026That Time I Got Reincarnated as a Slime the Movie: Tears of the Azure SeaMio (voice)
Television YearTitleRoleNotes2017Re:MindNao KosakaEpisode 13; episode lead role 2020DasadaYuria Sada2024Dear RadianceSaiin no ChūjōTaiga drama2025–2026Strobe EdgeSayuri Uehara2 seasons2026Maison PrisonSachi HashimotoKidnap GameHonoka ToedaEpisode 2
Commercials
FineToday (2022) Sony Assurance (Sony Financial Group) (2022–present) Kansai Electric Power Company (2024–present) Benzablock Premium DX (Alinamin Pharmaceuticals) (2025)
Music video YearArtistTitleNotes 2019Thinking Dogs"Spiral"The Japanese Doll theme song
Radio Dragon Quest of the Stars presents Hinatazaka46 Nao Kosaka's Kosaka-na Radio (Tokyo FM, 2021) Sony Assurance Quest for the Future (J-Wave, 2023–present)
Bibliography
TitleRelease datePublisherISBNJune 29, 2021ShueishaTriangle Magazine 02 (photo collection)January 23, 2024Kodansha
Notes
References
External links
at Non-no at Seventeen