Major General Mark J. O'Neil assumed duties as the USARAK Commander on 12 July 2017. He graduated from Norwich University on 28 May 1986 earning his commission as an Infantry Officer from Norwich University's Reserve Officer Training Corps. He began his career as a Platoon Leader, Company Executive Officer and Scout Platoon Leader with the 1st Battalion, 5th Cavalry Regiment, 1st Cavalry Division, Fort Hood, Texas.

Throughout his career, Major General O'Neil served in key staff and command positions for both Army Units and Special Operations Organizations. He served as a Battalion Logistics Officer and later Rifle Company Commander with the 1st Battalion, 27th Infantry Regiment, 25th Infantry Division, Schofield Barracks, Hawaii. In April 1994, he joined the 3rd Battalion, 75th Ranger Regiment, Fort Benning, Georgia, where he served as a Battalion Training Officer, Assistant Operations Officer, and Rifle Company Commander, and later as a Liaison/Plans Officer with Headquarters and Headquarters Company, 75th Ranger Regiment.

In 1998, Major General O'Neil joined a special operations organization where he served in every key leadership position from Troop Commander, Selection and Training Commander, Squadron Commander, Deputy Commander for Operations, and finally as the Commander of the organization from July 2009 to July 2011. He also completed an assignment as the Chief, Current Operations Division for the Joint Special Operations Command.

From August 2011 to December 2012, Major General O'Neil served as the Executive Officer to The Chief of Staff, United States Army. He then transitioned to the Fort Drum, New York to serve as the Deputy Commanding General - Operations for 10th Mountain Division. In March 2015, he became the Deputy Commanding General - Training for the Combined Arms Center at Fort Leavenworth, Kansas. His deployments include peacekeeping operations in Bosnia and 15 deployments in support of overseas contingency operations in Afghanistan for Operation Enduring Freedom and Iraq for

Operation Iraqi Freedom and Operation New Dawn.

Major General O'Neil's military awards and decorations include the following: Defense Superior Service Medal, Legion of Merit (Three Oak Leaf Cluster), seven Bronze Star Medals (one Valor device), Defense Meritorious Service Medal (one Oak Leaf Cluster), Meritorious Service Medal (one Oak Leaf Cluster), Joint Service Commendation Medal, Army Commendation Medal (two Oak Leaf Clusters), Ranger Tab, Combat Infantryman Badge, Combat Action Badge, Expert

Infantryman Badge, Military Free Fall Jumpmaster Badge, Master Parachutist Badge and the Air Assault Badge.

His educational degrees include a Bachelor of Science in Physical Education from Norwich University and Masters of Military Arts and Science from the U.S. Army Command and General Staff College at Fort Leavenworth, KS.