Sook Nyul Choi was born in Pyongyang, North Korea. She immigrated to the United States to pursue her college education.

Choi earned her B.A. from Manhattanville College in 1962 and became a school teacher in New York. She moved to Cambridge, Massachusetts, where she is now a full-time writer.

Choi's native language is Korean. As a young refugee from North Korea during the Korean War, Choi writes about her own experience through her heroines in her books. She said, "I now have two countries, my native country of Korea, and my adopted country, the United States, through my writing, I want to bring to life the history and culture of Korea to share with all my American friends."

In her first picture book, The Year of Impossible Goodbyes(1991), Choi writes about the topic of an immigrant's adjustment to life in the United States through the story of the 10-year-old Sookan and her life in Korea during the aftermath of World War II. The book won numerous awards including Best Books for Young Adults, ALA Notable Book and Judy Lopez Book Award by the National Women's Book Association. It has been translated into several languages including Korean, French, Italian, and Japanese.