Keiko Harada's career as a composer began with her improvisations on the piano as a child. She studied composition, conducting, piano and chamber music at Toho Gakuen school of Music where she graduated in 1993 with a Master's degree in composition. She also studied with Brian Ferneyhough.

Harada's works have won numerous awards including the 62nd Music Competition of Japan Awards, Akiyoshidai Prize and the 2001 Akutagawa Prize. She has received grants from many foundations including the Nomura Cultural Foundation, the Asahi Newspaper Cultural Foundation, The Japan Foundation, Canada Council for the Arts, Internationales Musikinstitut Darmstadt, Royamont Foundation, and Rockefeller Foundation (ACC). Most of her works have been commissioned by leading international festivals and performers including ICTUS ensemble, Nieuw Ensemble, Ensemble MODERN, ELISION, Tokyo Philharmonic Chorus, Takashi Yamane, Toshiya Suzuki, Mayumi Miyata, Michael Svoboda, Yo-Yo Ma, Stefan Hussong. In recent years Harada has done collaborative works for dance, theatre and film sponsored by leading international festivals. She established the Ensemble Manufacture for contemporary music in 1989. Since 2000, she has chaired the executive committee of SOUND GEAR, a project bringing together musicians from various parts of world focusing on theatrical new music. She is currently teaching composition and theory at Toho Gakuen.