Rear Admiral Dur was commissioned in 1965 from the NROTC program at the University of Notre Dame. His first assignment was duty under instruction at the University of Notre Dame as a scholarship recipient, and in June of 1966 he earned a Masters degree in Government and International Studies with a specialization in Soviet East European Area Studies. His first sea assignment was aboard the USS Little Rock (CLG-4), the 6th Fleet Flagship, as Radio Officer and subsequently as the Assistant Fleet Scheduler on the embarked staff. Following a brief tour at the Naval Intelligence Command, he reported aboard USS Stickell (DD-888) and subsequently USS Charles H. Roan (DD-853) while deployed in the North Atlantic and the Mediterranean. Following graduation from the Naval Destroyer School in July 1970, he reported as Operations Officer in USS Knox (DE-1052) and made the maiden deployment of that class to the Western Pacific. Following a second deployment of the USS Knox to the combat theater in southeast Asian waters, he was assigned to Harvard University as a Scholarship recipient and received the Masters in Public Administration (1973) as well as the PhD in Political Economy and Government (1976).
After completing the Command and Staff Course at the Naval War College in 1975, he reported aboard USS Waddell (DDG-24) as Executive Officer and served in that ship until June 1977 whereupon he reported to the Office of the Chief of Naval Operations in the Strategy and Plans Division. In 1978 he was transferred to the Office of the Secretary of Defense where he served in the Planning and Requirements Directorate and as Military Assistant to the Deputy Undersecretary (Policy). In June of 1980 he assumed command of the USS Comte De Grasse (DD-974) and completed two deployments to the North Atlantic and the Mediterranean.
Following this command tour in August of 1982, he reported to the Executive Office of the President to serve on the staff of the National Security Council as a Director of Political Military Affairs and as Military Assistant to the President's Special Envoy to the Middle East. In November of 1984 he reported as Executive Assistant to the DCNO Plans Policy and Operations. In August of 1985 he assumed command of the USS Yorktown (CG-48) and completed deployments to the Caribbean and Mediterranean. While under his command, Yorktown was selected the Battle E winner in Cruiser Destroyer Group Eight in two successive years. The ship also participated in several Gulf of Sidra exercises and most notably in the last incident of the Cold War, being rammed by a Soviet destroyer while transiting south of the Crimean Peninsula in February 1988. In April of 1988 he reported to the Office of the Secretary of the Navy as Executive Assistant and Senior Naval Aide to the Secretary.
Following selection to Flag Rank in 1989, he was assigned as Defense Attache to France. While in that assignment and during operation Desert Storm, he worked to ensure the integration of French military forces in combined operations against Iraqi forces, and facilitated the basing of US strategic tanking assets at French air bases. For his contributions in that capacity, he was inducted by the Defense Intelligence Agency into the Defense Attache Hall of Fame. In June of 1991 he assumed command of Cruiser Destroyer Group Eight and the Saratoga Battle Group, which included a deployment to the Mediterranean and the initial US show of force in the Adriatic in response to critical developments in the former Yugoslavia.
Following this command tour, he reported to the Office of the CNO as the Director of the Strategy and Plans Division and subsequently as the Assistant DCNO Plans, Policy, and Operations. While serving in the latter assignment, he was elected to the Council on Foreign Relations.
During his service Rear Admiral Dur was awarded the Defense Distinguished Service Medal, the Distinguished Service Medal, the Defense Superior Service Medal, the Legion of Merit, the Meritorious Service Medal and the Combat Action Ribbon as well as various campaign medals. In addition, for his service in France, he was awarded the French Ordre nationale du Merite in the grade of Commandeur, and he serves as the US member of the French Academie de Marine.