William Pene du Bois was born on May 9, 1916, in Nutley, New Jersey. He attended Miss Marstow's School in New York and in 1924 moved to France, where he studied at Lycee Hoche in Versailles until 1928 and at Lycee de Nice the following year. In 1930 he returned to New Jersey, where he studied at the Morristown School until 1934. Du Bois served in the U.S. Army from 1941 to 1945. After his discharge from the army, he became a correspondent for Yank magazine and later became an art editor and designer for the Paris Review.

Du Bois has been a prolific author and illustrator of books for children and for young adults. His first work of fiction for children was Elizabeth, the Cow Ghost (1936), followed by Giant Otto (1937), a book about a giant otter-hound who befriends the Sphinx in the course of his extraordinary adventures. The many sequels of this book include Otto at the Sea (1958), Otto in Texas (1959), and Otto in Africa (1961). Du Bois has won several book awards, including the New York Herald Tribune Spring Book Festival Award in 1947 and 1956, and the Newbery Medal in 1948 for The Twenty-One Balloons.

Du Bois's fiction displays tremendous variety, but several of his books share a common comic themea character's commitment to excessively eccentric behavior. Du Bois has also written a series of books concerning figures who represent the seven deadly sins, all of which are obvious examples of excessive behavior. One such is Porko von Popbutton, who quite literally embodies gluttony, and another is Bandicoot, who is the essence of greed.

Du Bois's talent as an illustrator is also impressive. As well as illustrating all of his own works, he has illustrated books by other authors including Rumer Godden, Isaac Bashevis Singer, George MacDonald, and Jules Verne.