She began to sing traditional Japanese music when she was four years old. Later, at the age of 15, Rikki was the youngest winner ever to win the "Grand Prix" of the Japanese traditional folk music awards (known as All Japan Minyo awards). She first performed in Tokyo, Japan, at the prestigious Festival Konda Lota in 1992. She released her first single "Maten no Hoshi" (which means "Sky Full of Stars") in December 1993, originally released in the Kyūshū region of Japan. Shortly thereafter, she produced debut album, Kaze no Koe.
Rikki is widely known by gamers as the singer of the Final Fantasy X main theme, Suteki da ne, released as a single on July 18 2001. Other songs on the single include the Instrumental version of Suteki Da Ne, "Pure Heart" (a vocal arrangement of Aeris' Theme from Final Fantasy VII), and a new song entitled "Tsukisama" (which means "The Moon"). One reason why Nobuo Uematsu and Kazushige Nojima chose her to perform Suteki Da Ne (translated into English as "Isn't It Wonderful?") is that she is very famous in Japan as a traditional folk singer and he believed that her voice is rather nice and gentle and that it has a higher pitch than the voices of mainstream Japanese singers. Rikki was 26 years old at the time of Final Fantasy X's release. Many professional and amateur singers were inspired by her singing voice and ability to make combinations and mixtures of pop and rock music.
In 2006, Rikki joined the band Sound Horizon for the release of "5th Story CD: Roman" She was involved in Sound Horizon's releases until 2008, when she gave birth to twins and returned to Amami Oshima, as she said in her blog.