Born in Korea, An Na grew up in San Diego, California. As a child she was a voracious reader, shutting herself up in the family's bathroom (the only room with a lock on the door) to read in peace. In An Na's first novel, A Step From Heaven, the protagonist, Young Ju Park, also makes the trip from Korea to California and grows up straddling the two cultures.
A former middle school teacher of English and history, Na began writing A Step From Heaven when she took a children's literature class, then finished the book when she enrolled in an M.F.A. program. As a first novelist, An Na was something of a phenomenon. She was hailed immediately for her "exquisite voice" by the New York Times reviewer. A Step From Heaven won the Michael L. Printz award for excellence in young adult literature, and was a finalist for the National Book Award. It was included on numerous "best book" lists.
An Na visits schools frequently to talk about her book. She hopes, especially, to inspire Asian American children: "I think when writers go into schools, they allow children to imagine that this could be them... If more Asian American writers visited schools, I think more Asian American children would dare to dream of becoming artists."
When asked by interviewer Cynthia Leitich Smith about advice she'd give other authors thinking about writing for a young adult audience, An Na says:
The best books and writers create stories that leave room for the reader to understand a character and their motivation. You are heartbroken when a character makes a decision that you feel is wrong, but you understand why they chose to act in the way that they did. That type of empathy is so much better than some story that bluntly hits you over the head with a moral lesson.
An Na considers Frank McCourt's Angela's Ashes and Sandra Cisneros's The House on Mango Street among the influences on her writing and also admires the work of Madeleine L'Engle and of her first writing teacher, Jacqueline Woodson.
An Na is a graduate of Amherst College, and received an M.F.A. from Vermont College.