#VeteranOfTheDay Army Veteran Mark O’Neil

December 10, 2022: Mark O’Neil

Maj. Gen. Mark O’Neil led an extensive career during his service in the United States Army. From the 75th Rangers to Delta Force to Chief of Staff of the Army, he met every challenge head-on. His attitude toward service, in his own words: “Let’s get ready to get after it.” This mentality led him well through multiple commands and numerous deployments across the world.

O’Neil was born in New York in June 1964 to Donald and Shirley O’Neil. He attended Norwich University, where he studied physical education and lettered in football and track. In recognition of his physical ability, he was inducted into the Norwich University Athletic Hall of Fame in 1986. After graduating, he was commissioned as a second lieutenant, branching infantry.

Between 1986 and 1998, O’Neil served with the 1st Cavalry Division, 25th Infantry Division, 3rd Battalion of the 75th Ranger Regiment and the headquarters component of the 75th Ranger Regiment. His roles progressed from platoon leader to rifle company commander, and he gained experience as a logistics, training, operations, and liaison/plans officer.

In 1998, after a rigorous selection process, O’Neil was assigned to the 1st Special Forces Operational Detachment-Delta, known as Delta Force. In the years after the attack on Sept. 11, 2001, he deployed a total of 15 times to Iraq and Afghanistan in support of Operations Enduring Freedom, Iraqi Freedom and New Dawn, and was responsible for the success of incredibly dangerous and complex missions.

From 2009 to 2011, O’Neil served as the commander of Delta Force and as the Chief of the Current Operations Division for the Joint Special Operations Command. As commander, he served as the key coordinator during all training exercises and operations.

In 2011, O’Neil was designated the Executive Officer to the Chief of Staff for the U.S. Army. After a promotion to brigadier general in 2013, he became commander of the 10th Mountain Division, where he served for two years until a promotion to major general. In 2015, O’Neil was made the deputy commanding general for the Combined Arms Center-Training command. While there, he oversaw efforts to develop new training plans and programs for the Army. His final commands from 2016 to 2019 led him to Hawaii and Alaska, where he served as the Chief of Staff for the United States Army Pacific and the commanding general for the United States Army Alaska.

During his career, O’Neil completed Ranger, Airborne and Air Assault schools, and became a master and free fall parachutist. He was also awarded a Defense Superior Service Medal, a Legion of Merit with three Oak Leaf Clusters, a Bronze Star with seven Oak Leaf Clusters and a “V” for valor in combat, a Combat Infantryman Badge, along with other numerous commendation and campaign medals.

We honor his service.

Writer: Jackson Baker

Editors: Delaney Tracy, Cynthia Xu

Researchers: Chenou Yang, Ryan Nishiyama

Graphic Designer: Samantha Mejia