Kyungsun Suh was born in Seoul, Korea. She studied composition and theory at the Seoul National University, graduating with bachelor's and master's degrees, and at the University of Massachusetts at Amherst. After completing her studies she took a position teaching at Hanyang University in 1974. Her works have been performed internationally.
Suh served as president of the Korean Society of Women Composers from 1993–97. She organized the Asian Contemporary Music Festivals in Seoul and Suwon in 1993 and 2002. She received the Okwan (Jade) Medal of Culture from the Korean Ministry of Culture and Tourism, and an Arts Award from the Arts Council of Korea in 2005. She is professor Emeritus at Hanyang University.