He lives in Brooklyn, New York with his family. Mo began his career as a writer and animator for television, garnering 6 Emmy awards for his writing on Sesame Street, creating Nickelodeon's The Off-Beats, Cartoon Network’s Sheep in the Big City and head-writing Codename: Kids Next Door. Mo’s work books have been translated into a myriad of languages, spawned animated shorts and theatrical musical productions, and his illustrations, wire sculpture, and carved ceramics have been exhibited in galleries and museums across the nation.

The New York Times Book Review called Mo “the biggest new talent to emerge thus far in the 00's.'

In addition to such picture books as Leonardo the Terrible Monster, Edwina the Dinosaur Who Didn’t Know She Was Extinct, and Time to Pee, Mo has created the Elephant and Piggie books, a series of early readers, and published You Can Never Find a Rickshaw When it Monsoons, an annotated cartoon journal sketched during a year-long voyage around the world in 1990-91. #1 New York Times Bestselling author and illustrator Mo Willems is best known for his Caldecott Honor winning picture books Don’t Let the Pigeon Drive the Bus and Knuffle Bunny: a cautionary tale.

Elephant and piggie waiting is not easy