The Newbery Award is given annually to the best children's book written in English. While "Smile" is a highly acclaimed graphic novel, it is not eligible for the Newbery Award because it is not considered a "book" in the traditional sense. The Newbery Award is specifically for fiction books.
However, "Smile" has won several other awards, including the Eisner Award for Best Publication for Kids (ages 9-12) and the YALSA Award for Excellence in Nonfiction for Young Adults.