O'Meara is 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, U.S. Army. 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 Reserves in 2002, after 36 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-Newark, Richard Stockton College, Kean University and Monmouth University, where he teaches courses in Security Studies, Human Rights, International Law, and History.
He holds a Research Fellowship at the Stockdale Center for Ethical Leadership, United States Naval Academy and 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.
In July 2006, General O'Meara spoke about genocide and torture at the New Jersey Governor's School of Public Issues and the Future of New Jersey.
Open letter to President Bush of September 7, 2004
On September 7, 2004 O'Meara and seven other retired officers wrote an open letter to President Bush expressing their concern over the number of allegations of abuse of prisoners in U.S. military custody. In it they wrote:
- "We urge you to commit – immediately and publicly – to support the creation of a comprehensive, independent commission to investigate and report on the truth about all of these allegations, and to chart a course for how practices that violate the law should be addressed."