Mark's illustrations have appeared in children's books and magazines such as Appleseeds, Cobblestone and Cricket. A book that Mark wrote and illustrated for upper elementary readers, Raising 'La Belle,' about an early colonial shipwreck recovered from a Texas bay won the Western Writers of America Spur Award for "best western juvenile nonfiction book" of 2003.

As a contributing editor for American Artist Watercolor magazine, 
Mark interviewed many of the top children's book artists who use water-based painting mediums, including Jerry Pinkney, E.B. Lewis, Emily Arnold McCully, Patricia Polacco and Ted and Betsy Lewin.  

He teaches classes in children's book illustration at the Art School of the Austin Museum of Art in Austin, Texas and his online course, Make Your Splashes - Make Your Marks!, which has attracted students around the U.S. and several countries. 

Escape from Illustration Island named his blog, How to Be A Children's Book Illustrator one of the 12 "top online resources on children's book illustration."

Aztec marketplace, illustration by Mark Mitchell for Appleseeds