Following graduation from Knox College, Ryan served on active duty for the United States Marine Corps from 1988 to 1992, and again following Law School graduation as a judge advocate from 1995 to 1999. Ryan served in units within the II &amp; III Marine Expeditionary Forces as a Staff Officer, Company Commander, Platoon Commander, and Operations Officer. Judge Ryan's tours included deployments to the Philippines, during a coup attempt, and to Saudi Arabia during Desert Shield and Desert Storm. As a Judge Advocate General (JAG) officer, Ryan served as a Trial Counsel and Chief Trial Counsel in Okinawa, Japan and Quantico, Virginia. Ryan was then selected by General Charles C. Krulak, Commandant of the Marine Corps, to serve as his Aide de Camp.