Demi was born in Cambridge, Massachusetts. She studied art at the Instituto Allende in Guanajuato, Mexico; with Sister Corita at the Immaculate Heart College in Los Angeles; at the M. S. University in Baroda, India, while on a Fulbright scholarship; and at the China Institute for Arts in New York City. Her husband, Tze-si Jesse Huang, introduced her to the religion, folklore, ancient culture, and history of China, after which she became intrigued by the stories she read about Marco Polo.

Demi is the author and illustrator of more than three hundred children's books, including picture book biographies of spiritual leaders such as Jesus, Buddha, the Dalai Lama, Gandhi, and Muhammad. Su Donpo: Chinese Genius retells and illustrates true Chinese leadership and heroism, and numerous folktales such as The Empty Pot and Liang and the Magic Paintbrush transmit the wonder and magic of China. Her work has received many awards and ac-colades, among them the Christopher Award, which recognizes individuals whose work makes a positive difference in the world, and the Middle East Book Award. Her titles have been designated American Library Association Notable Children's Books, New York Times Best Illustrated Books, Notable Books for a Global Society, and American Bookseller Pick of the List Books.