After graduating from UCLA with a degree in Fine Art, Clarke worked as an art director/designer (though he didn't know much about typography or design), before starting a career as an illustrator in 1990. Since then, he has gone on to work for various publications such as TIME, Rolling Stone, Atlantic Monthly, and The New Yorker. Corporate clients include Target, Volkswagen, Purina, Xerox, and Fox Television. His work is mainly traditional, working in watercolor, pencil, and pen & ink, and his subject matter often deals with the interaction between humans and animals. Even going so far as to personify the animals, allowing for a more humorous interaction between two different species. His colors are washy, and at time show the texture of whatever paper he happens to be working on.