[2] His studies were paused when he served the United States Army Air Forces in World War II, as a captain in intelligence.

Kim is known for his vocal and music theater works, many of which use texts by Samuel Beckett, and for his expressive, often tonal style.

"[7] In 1971 and 1972, Kim collaborated with his wife dancer Mimi Kagan on the work "Exercises en Route", which toured and featured text by Samuel Beckett, and soprano soloist performer Benita Valente.

[8] His art songs have been performed by Bethany Beardslee, Karol Bennett, Merja Sargon, Benita Valente,[8] and Dawn Upshaw.

[1] Kim was married three times, to Nora Philipsborn (in 1947), dancer Mimi Kagan (in 1956),[10] and Martha Potter (in 1977); and he had two daughters.