In college, Dav met a teacher who encouraged him to write and illustrate for kids. He took her advice and created his first book, World War Won, which won a national competition in 1986. Dav made many other books before being awarded the California Young Reader Medal for Dog Breath (1994) and the Caldecott Honor for The Paperboy (1996).

In 2002, Dav published his first full-length graphic novel for kids, called The Adventures of Super Diaper Baby. It was both a USA Today and New York Times bestseller. He has published more than seventy books for children, including the bestselling Dog Man and Cat Kid Comic Club graphic novels.

Dav's stories are semi-autobiographical and explore universal themes that celebrate friendship, empathy, and the triumph of the good-hearted.

When he is not making books for kids, Dav loves to kayak with his wife in the Pacific Northwest.