Kaoru Mizuhara is a Japanese voice actress from Chiba Prefecture, Japan, born on June 26. Her path to voice acting was influenced by her mother, who worked as an in-store announcer at a department store, sparking her interest in a broadcasting career. Before her voice acting debut, she was scouted while working as an announcer herself. She began her career in 2006 and has been active in the industry since then, with her early agency affiliations including Media Force and later Across Entertainment.

Mizuhara is widely recognized for two significant roles that launched her career. One is the character Misao Kusakabe in the 2007 anime series Lucky Star. Her performance became notable for a distinctive ad-lib in episode eighteen, where she added a nonsensical "vuah" sound to the end of a sentence for her character. This moment resonated strongly with audiences, contributing to a cult following for the character and spawning internet memes. The popularity was such that an additional character album featuring Misao Kusakabe was released, expanding on the originally planned series of albums. The other defining role of her early career was as Yomi Isayama in the 2008 series Ga-rei -Zero-.

Throughout her career, Mizuhara has demonstrated her versatility by voicing a wide array of characters across different series. Her filmography includes roles such as Nana Chigusa in Nana to Kaoru, Mitsuki Kaibara in Scan2Go, Kusano-sensei in Hanamaru Kindergarten, Takashi Tobe in Sora o Miageru Shōjo no Hitomi ni Utsuru Sekai, Haruna in anohana: The Flower We Saw That Day, Nakamura-Sensei in Nichijou - My Ordinary Life, Natsume Fuji in Nōgyō Musume!, Fumiya Ninomiya in Wandering Son, Luka in Bodacious Space Pirates, and shrshr in the gdgd Fairies series and its film. She also voiced Saphir in Kiddy Girl-AND, Kagefusa Manyū in Manyū Hiken-chō, and Tokiyo Himote in HIMOTE HOUSE: A share house of super psychic girls. In addition to these, her notable roles include Hideyoshi Kinoshita in the Baka and Test drama CD, Rea Amano in Future Diary, and Puck in the Berserk anime adaptations.

Beyond animation, Mizuhara has contributed to other areas of voice acting. She has performed character songs for series like Lucky Star and Ga-rei -Zero-, for which she also performed the first ending theme song, Yume no Ashioto ga Kikoeru. Her work in radio programs has been a consistent part of her career, including hosting roles for shows related to Lucky Star and Ga-rei -Zero-. She also lent her voice to the Japanese dubs of foreign productions, such as the live-action film Drive-Thru and the animated series Lego Ninjago: Masters of Spinjitzu. Mizuhara also took on the role of manga supervisor for a series titled Seiyū Gekijō Papaion! Mizuhara-san, which was based on her experiences.