Captain Lehmer enlisted in the Marine Corps July of 2003 and completed basic training at Parris Island, South Carolina, in August of 2004. He was assigned to Marine Wing Support Squadron (MWSS) 471 Detachment Bravo at Selfridge Air National Guard Base (ANGB) as a combat engineer in the Marine Corps Reserves.
Captain Lehmer was commissioned in the U.S. Marine Corps in January 2008 and was assigned to Delta Company, The Basic School (TBS) in Quantico, Virginia.
After graduating TBS, he reported to the Basic Communication Officer Course (BCOC) in Quantico, Virginia.
Upon completion of BCOC as the Honor Graduate in July of 2009, he was assigned to 8th Communication Battalion, II Marine Expeditionary Force (MEF) Headquarters Group (MHG), II MEF, Camp Lejeune, North Carolina. In October, Captain Lehmer was sent forward to join B Company of 8th Communication Battalion at Al Asad Airbase, Iraq. He served as the transmission and headquarters platoon commander within the detachment.
Upon redeployment, Captain Lehmer became the operations officer and data platoon commander of B Company, 8th Communication Battalion. In July of 2011, Captain Lehmer deployed again with B Company as the data platoon commander to Camp Leatherneck, Afghanistan. Upon redeployment, he was moved to Headquarters Company.
In February of 2012, Captain Lehmer served as the Headquarters Company Commander, 8th Communication Battalion.
In July of 2012, Captain Lehmer was assigned as a United States Cyber Command Liaison in the Cyber Support Element to United States Central Command. He served as a Defensive Cyber Operations, Offensive Cyber Operations, and Targeting and Fires Planner within the Cyber Support Element.
In September of 2015, Captain Lehmer returned to II MEF for duty as the Headquarters and Service Company Commander, 2d Radio Battalion, II MHG. He served as the H and S Company Commander through February of 2017 and briefly served as the S-6 Officer for 2d Radio Battalion from February of 2017 through May of 2017.
Capt Lehmer assumed command of Marine Corps Detachment-Fort Gordon in June of 2017.
Captain Lehmer is a graduate of the University of Michigan-Ann Arbor. His personal decorations include Joint Commendation Medal, Navy and Marine Corps Commendation Medal, and the Navy and Marine Corps Achievement Medal.