O'Meara is a retired Brigadier General (USA) and a combat veteran of the War in Vietnam. Following his Vietnam service he earned a law degree and joined the Judge Advocate General’s Corps. For two decades, while serving in the U.S. Army Reserve, O’Meara acted as senior partner in the litigation firm, O’Meara & Hight. He retired from the United States Army in 2002, after 35 years of service.

Following his retirement he earned graduate degrees in History and International Relations and took up teaching posts at the Division of Global Affairs, Rutgers University and Richard Stockton College where he has taught courses in Security Studies, Human Rights, Terrorism, Genocide, War Crimes, International Law and Criminal Justice. He holds a Research Fellowship at the Stockdale Center for Ethical Leadership, United States Naval Academy. His research interests include military sociology, governance generally and international law issues arising out of the transformation of institutions as a result of globalization and emerging technologies. He continues to serve as Adjunct Faculty with the Defense Institute of International Legal Studies where he has taught rule of law, governance, and peacekeeping subjects in such diverse locations as El Salvador, Peru, Cambodia, Rwanda, Philippines, Chad, Sierra Leone, Guinea, Ukraine, Moldova, and Iraq. He is a qualified Emergency Medical Technician and served at the World Trade Center Site in the months after 9/11.