She is best known for writing the 2015 young adult novel Everything, Everything, a New York Times best seller and the basis of a 2017 film of the same name.

[4][7] Her husband, Korean American graphic designer and author David Yoon, drew the illustrations.

[12] Yoon's second book, The Sun Is Also a Star, was released in November 2016, and also reached number one on the New York Times Best Seller list.

[19] The movie, directed by Ry Russo-Young, and starring Yara Shahidi and Charles Melton, was released on May 17, 2019.

[9][21][22] She contributed to Because You Love to Hate Me, an anthology of short stories written by 13 YA authors who were paired with 13 BookTubers, who provided writing prompts.

[24] In Spring 2023, Yoon launched a young adult publishing imprint with her husband David called Joy Revolution Books.