Rumi Shishido is a Japanese voice actress and singer born on November 6, 1973, in Fukuoka Prefecture, Japan. She was raised in Hiroshima from the age of two. Her career in entertainment began not in voice acting, but as an idol singer. In 1989, at sixteen, she won a major contest with 85,000 entrants, which led to her debut on a television commercial and a recording contract with Sony Records. Her debut single, Cosmic Rendezvous, was released in 1990, and she performed under the nickname Run Run. After two years, she chose not to renew her contract to pursue other creative paths, becoming an independent artist. Her first independent album, Set Me Free, released in 1995, was praised by The New York Times for her "ripe, melodic voice".

Her entry into voice acting came in 1992 with a small role in the OVA series KO Beast. A pivotal moment occurred when a producer from Toei Animation heard her distinctive speaking voice on her album and encouraged her to audition for anime roles. Her breakthrough leading role came in 1995 as Mikako Koda in the series Neighborhood Story. That same year, she auditioned for the lead in Ojamajo Doremi and, while she did not get that part, was cast as the character Onpu Segawa. This role proved to be a major boost to her popularity and became one of her most iconic and enduring performances. She would go on to reprise the role of Onpu across numerous Ojamajo Doremi sequels, films, and specials, including Mōtto! Ojamajo Doremi and Looking for Magical DoReMi.

Shishido's career is marked by a wide range of roles across many popular series. She had recurring roles in the Jewelpet franchise, voicing the characters Diana and Luna across multiple seasons including the original Jewelpet, Jewelpet Twinkle, and Jewelpet Kira Deco. She also voiced June Amō in Pretty Rhythm Rainbow Live and its film sequel King of Prism. In the long-running series Reborn!, she voiced the character Viper, also known as Mammon. Her filmography includes roles such as M.O.M.O. in the Xenosaga: The Animation series and video games, Rosemary Applefield in Ashita no Nadja, Lopmon in Digimon Frontier, and multiple characters in Welcome to the N.H.K., including Nanako Midorikawa and the idol character Pururin. She has also taken on roles in live-action films, appearing in the Nana live-action movies.

Throughout her career, Shishido has demonstrated versatility, voicing characters ranging from magical girls and fairies to more serious roles. She has collaborated with the work of manga artist Ai Yazawa, providing voices for characters in adaptations of Neighborhood Story, Paradise Kiss, and the Nana video game. In addition to her voice acting and continued independent music career, she is also an illustrator.