Hartman is a freelance illustrator and author. Her illustrations have appeared in New York Magazine, American Baby, Mpls./St. Paul Magazine, The Hartford Courant, Seattle Monthly, St. Louis Magazine, AAA Travel Magazine, Midwest Living, Threads, the Minneapolis Star Tribune, Inside Counsel, and the Baltimore Sun. Some of her clients include Office Depot, Encyclopedia Britannica, HGTV, Nature Made, Baxter, Sterling Publishing, American Greetings, Northeastern University, National Center for Youth Issues, Lerner Publishing, Target, Innovative Kids, and the Minnesota State Fair. Her work has won awards from the Los Angeles Society of Illustrators and the Association of Educational Publishers (AEP).