Ui Miyazaki is a Japanese voice actress and singer born on August 23, 1981, in Tokyo, Japan. After graduating from the Japan Narration Acting Institute, she furthered her training at RPE and the Human Academy. She made her debut in 2004 with a role in the television anime Magical Kanan. Early in her career, she was affiliated with the agency RAMS, where she was considered a representative voice actress alongside Sakura Nogawa during the mid-to-late 2000s. In 2013, she left RAMS and joined 81 Produce.

Miyazaki gained widespread recognition for her role as Aisia in the 2005 anime series D.C.S.S. (Da Capo Second Season). This character became one of her most iconic and helped establish her popularity. She would later return to the Da Capo series in 2013 to voice Charles Yoshino in D.C.III. Her career during this period was marked by a steady stream of leading roles in various anime adaptations. Some of her notable television anime roles include Kiriko Takana in Kanokon: The Girl Who Cried Fox, Iroha Minamoto in Sumomomo Momomo: Chijō Saikyō no Yome, Remon Natsume in Strawberry Panic!, Suzuho Hasegawa in Magician's Academy, Rin Hiroishi in Master of Martial Hearts, Hamii in Shokupan Mimi, and Waragetcha Black in Master of Epic: The Animation Age. She also played Hakone Oumi in Juden Chan, Kirino Konosaka in Gift - eternal rainbow, and Elis Shihō in Night Wizard The Animation. Her voice work extended significantly into video games, where she is known for roles such as Orica Nestmile in the Ar tonelico series, Yuno Kasuga in Memories Off 6: T-wave, and Nanami Nishijō in Chaos;Head.

In addition to her voice acting, Miyazaki was also active as a singer. From 2005 to 2008, she was a member of the voice actor unit Clover with her colleague and friend Saito Momoko. She released several solo singles, many of which were used as theme songs for anime series in which she starred. Notable examples include "KURENAI," the opening theme for Night Wizard The Animation, and "PHOSPHOR," the opening theme for Kanokon: The Girl Who Cried Fox. Throughout her career, she has been involved in numerous radio programs and drama CDs related to her various roles, further connecting with her audience. Her work demonstrates a versatility that includes portraying characters who undergo emotional shifts, from innocent girls to darker, more complex personas, as seen in her roles in Gift ~eternal rainbow~ and Chaos;Head.