Marshall attended Dixie Jr. College before attending and graduating from BYU with a bachelor’s degree in international relations with an emphasis in foreign languages and a master’s degree in international relations with an emphasis in economics. Marshall graduated from the J. Reuben Clark Law School at Brigham Young University, where he served as Editor-in-Chief on the International and Comparative Law Journal.
Marshall was a partner in the firm of Duval Hansen Witt and Morley in northern Utah from 1995 until 2003. He started the predecessor of Witt Law in 2003. His practice is devoted to accidents and personal injury, criminal defense, family law, estate planning and mediation.