After high school, Warren enlisted in the Army as an infantryman. As part of the 3rd Infantry Division, he was stationed in Germany and witnessed the fall of the Berlin Wall. Warren’s commanding officers recognized his potential and helped him earn an appointment to the United States Military Academy at West Point. He graduated near the top of his class as a student of American history and mechanical engineering. As an officer, he led in The Old Guard, the 75th Ranger Regiment, and the 101st Airborne Division.