Miller, who was born in Germany, began his career as a certified public accountant. In 1976, he founded MMI, which specialized in purchasing and selling businesses. Miller has long been active with local organizations, including the University of Portland's Board of Regents, the Jewish Community Center of Portland, and the Oregon State Fair Commission. He and his wife, Sandi, generously endowed a scholarship for students who are naturalized U.S. citizens. In addition to receiving his MBA from the University of Portland, Miller also received a Doctorate of Humane Letters in 2009.