Karen Matsumoto, a native of Chiba Prefecture, was born on 28 March 2002.[1] She was enrolled as a piano major at a junior college specializing in music.[2] She was also active as a TikToker.[1]
After Matsumoto posted on social media about her desire to become an idol, an acquaintance introduced her to Asobisystem after discovering the post.[2] In February 2022, she was announced to be one of the inaugural members of Fruits Zipper, an idol group which is part of Asobisystem's Kawaii Lab. project.[3] She was one of the first three members to join the group when it was formed.[4] Fruits Zipper marked her debut as an idol.[3]
On 13 September 2023, Matsumoto received her own released edition of Fruits Zipper's single "Watashi no Ichiban Kawaii Tokoro".[5] In June 2025, she formed the new unit PiKi with Cutie Street member Haruka Sakuraba.[6] Shiho Namayuka of QJWeb described Matsumoto as the "true embodiment" of the group's New Kawaii concept.[7] In August 2025, her birthday fan event was delayed by five days due to health concerns on Matsumoto's part.[8] She was ranked runner-up in the "Female Idol / Artist" category in Model Press's 2026 Hit Predictions forecast.[9]
In January 2026, Matsumoto received supportive reactions from social media users after she indirectly confirmed that she likes Suzuka, a member of Atarashii Gakko!, after the two appeared together on Count Down TV's 2025 New Years' Eve special.[10] She has a cat named Matsumoto Ono Komachi.[11] She also has two younger brothers.[7]