Professor Hartman teaches a variety of courses in the School of Business Administration, including Business Law, Business Ethics, and Federal Income Taxation. He has served on many committees at the university, college, and school level, and has provided proofreading and editorial assistance for several books and numerous journal articles. In 2012, Professor Hartman was recognized by the students of Cedarville University as Faculty Member of the Year. Prior to joining the faculty in 1989, he was employed by Kellogg Corporation as a tax accountant and Ernst & Whinney as a staff accountant.