Marc served 35 years in the Canadian Forces, culminating in the top position of Commander of the Army with the rank of Lieutenant-General. In that position, at the strategic level of the Canadian Forces and the Department of National Defense, he contributed to the achievements of these organizations during one of the most important periods in recent times of operational commitment and transformation.
Since his retirement he has served as international civil servant with the UN. His first appointment from May 2008 to November 2008 was as the principal adviser to the Special Representative to the Secretary General of the UN Mission in Congo MONUC on Security Sector Reform. From November 2009 to May 2011 he was the Deputy Head of the International Security Sector Advisory Team (ISSAT). From May 2012 to February 2013 he was appointed by the Secretary general of the UN as the Adviser to President Alpha Condé of Guinea. Marc currently serves additionally as the Director of the Board of the Perley and Rideau Veterans's Health Center Foundation, whilst providing advisory capacity to ISSAT.
Marc holds an undergraduate degree in Political Science from the University of Ottawa, a Masters in Military Studies from the UK Royal Military College of Science and a Masters in Security Studies from the US Army War College. He has also attended both the Canadian Land Force Command and Staff College in Kingston in 1982 and the Canadian Forces Staff College in Toronto in 1984.