His paintings and drawings have been included in exhibitions in New York, Los Angeles, San Francisco, Paris, Tokyo, and the United Arab Emirates. A ten-year survey of Valentine's work was held in the Czech Republic in 2002–3. Between starting and finishing his BFA degree at the Columbus College of Art and Design, Valentine worked in a variety of positions, including assistant art director for a television station in Columbus, master screen printer in Chicago, and freelance illustrator for Warner Bros. Records in New York City.