LtGen Berger was commissioned as an infantry officer in 1981 following graduation from Tulane University. As a Lieutenant and Captain, he served as platoon commander in 1stMarDiv, and later as company commander and Battalion Operations Officer in 2d Reconnaissance Battalion during OPERATION DESERT STORM. He also served as Officer Selection Officer in Roanoke, VA.
As a field grade officer LtGen Berger was an instructor at Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) in Yuma, AZ; instructor at III MEF Special Operations Training Group; and served on the Joint Staff as a policy planner in the Strategic Plans and Policy Directorate, J-5.
LtGen Berger commanded 3d Battalion, 8th Marines from 2002 to 2004, deploying the Battalion first to Okinawa, and later to Haiti in support of Operation Secure Tomorrow. As a Colonel, LtGen Berger commanded Regimental Combat Team 8 in Fallujah, Iraq during OPERATION IRAQI FREEEDOM.
While serving as Assistant Division Commander of 2d Marine Division, he was appointed to the rank of Brigadier General. He then deployed to Kosovo, where he served for one year as Chief of Staff for KFOR Headquarters in Pristina. From 2009 to 2011 he served at Headquarters Marine Corps as the Director of Operations in Plans, Policies, and Operations. In 2012 he deployed to Afghanistan as the Commanding General of 1stMarDiv (forward) in support of OPERATION ENDURING FREEDOM.
LtGen Berger served as Commanding General, MAGTFTC, and Marine Corps Air Ground Combat Center from 2013 to 2014.