Tussing joined the Center for Strategic Leadership in October 1999 following nearly 25 years in the US Marine Corps. He is a distinguished graduate of both the Marine Corps Command and Staff College and the Naval War College and holds master’s degrees in national security strategy and military strategic studies. Tussing has served on three defense science boards, the Center for Strategic and International Studies’ Beyond  Goldwater-Nichols Study, and the senior advisory group for the Department of Defense “Strategy for Homeland Defense and Civil Support.”

He is a member of the board of experts for the University of California – Irvine Center for Unconventional Security Affairs and the Pennsylvania State University Homeland Defense and Security Council. Tussing also serves on the board of advisers for Long Island University’s Homeland Security Management Institute and the board of advisers of the Preparedness Leadership Council. In 2009, he served on Department of Homeland Security’s Homeland Security Advisory Council, assisting in the development of the Department’s first Quadrennial Homeland Security Review. In 2013, he served on an advisory council for the Secretary of Homeland Security. In May 2014, he was awarded an honorary doctorate in humane letters by Northwestern State University in recognition of his work in homeland security, homeland defense, and educational initiatives surrounding those regimes.