After graduating from Texas A&M University, Colonel Glenn commissioned in the United States Marine Corps in 1999. Initially assigned to 2nd Battalion, 3rd Marines, he served as a platoon commander and participated in two deployments to Okinawa, Japan. He also deployed to Southwest Asia as a security detachment commander serving under CTF-53 providing security for US Naval interests. While in Hawaii, Col Glenn also served as the Aide-de-Camp to the Deputy Commander of Marine Forces Pacific. In this capacity he was again deployed to Southwest Asia in support of Operation Iraqi Freedom and Operation Enduring Freedom.
In 2004 Col Glenn reported for duty to MCRD San Diego serving as a Series and Company Commander in 2nd Recruit Training Battalion. In 2007 he graduated from the Expeditionary Warfare School and was assigned to 3rd Battalion, 5th Marines as a rifle company commander and completed a deployed to Iraq. In 2009, he deployed again with 3rd Battalion, 5th Marines and served as the Maritime Raid Force Commander with the 31st Marine Expeditionary Unit (MEU).
In 2009 Col Glenn was assigned as the Marine Officer Instructor at Texas A&M University. During this assignment he earned a Master’s Degree in International Affairs from the George Bush School of Government and Public Service. In 2012 he was assigned to the 13th MEU and served as the assistant operations officer and operations officer. Col Glenn deployed with the 13th MEU supporting operations and exercises in CENTCOM, AFRICOM, and INDOPACOM’s areas of responsibility. In 2015 he attended the Marine Corps Command and Staff College in Quantico, Virginia. Upon graduation from Command and Staff College, Col Glenn served as an advisor to the Royal Saudi Marines and Royal Naval Special Forces for one year. Upon his return from Saudi Arabia, he served with Training and Education Command as the head of the Ground Standards Branch.
In 2018, Col Glenn assumed command of 2nd Battalion, 7th Marines and deployed in 2019 in support of Operation Inherent Resolve in Syria and Iraq. The battalion conducted various missions in six different countries throughout CENTCOM’s area of responsibly. In 2020, Col Glenn attended the Marine Corps War College and was subsequently assigned to the Joint Staff Directorate of Strategy, Plans, and Policy (J-5). In 2023, Col Glenn assumed command of the 13th Marine Expeditionary Unit.