Major General O'Donohue graduated from the College of William and Mary with a Bachelor of Arts in History and was commissioned in 1984.
Command assignments include: Commanding Officer, Charlie Company, 1st Battalion, 2nd Marines (1993-1995), Commanding Officer, 2nd Battalion, 5th Marines (2002-2004), Commanding Officer, 1st Marine Regiment (2009-2010), Commander, Marine Corps Forces Cyberspace Command (2015).
Staff assignments include: Ground Structure Planner, Headquarters Marine Corps (1988-1992); 8th Marines Operations Officer (1995-1996); Operations Officer, Joint Task Force Assured Response and Special Purpose Marine Air-Ground Task Force Liberia (1996); Tactics Instructor and Expeditionary Operations Program Director, Amphibious Warfare School (1997-2000); Operations Officer, 1st Marine Division (2001-2002); Assistant Chief of Staff G-7 / Division Combat Assessment Officer (2004); Deputy Branch Head, Secretary of the Defense's Office of Force Transformation (2005-2007); Branch Head, Ground Combat Element Branch, Plans, Policies and Operations, Headquarters Marine Corps (2007-2008); Assistant Chief of Staff G-3, 1st Marine Division (2008-2009); Director, Capabilities Development Directorate, Headquarters Marine Corps (2010-2012); Deputy Director for Force Management, Joint Staff J-8 (2013), Deputy Chief of Staff for Operations, ISAF Joint Command (2014).
He is a distinguished graduate of the Naval Postgraduate School, Amphibious Warfare School, School of Advanced Warfighting, and National War College. He has Masters of Science Degrees in Management and National Security Strategy.