Kim Sa-in was born in Boeun, North Chungcheon Province, in 1955. He has published two collections of poetry, Night Letters (bame sseuneun pyeonji, 1987) and Liking in Silence (gamanhi joahaneun, 2006), four collections of criticism, including A Deep Reading of the Novels of Park Sang-Ryung (2001), and a book of essays, A Warm Bowl of Rice (2006).
Following time in prison in the early 1980s he began writing poetry and co-founded the magazine Poetry and Economy. Among his awards are the Sin Dong-Yeop Grant for Writing (1987), the Modern Literature Prize for poetry (2005), and the Daesan Literature Award for poetry (2006). He teaches creative writing at Dongdeok Women's University, and hosts broadcast programs devoted to poetry and spirituality. In late 2010 he participated in the University of Iowa's International Writing Program.