Lieutenant Colonel Marksbury was raised in Corpus Christi, Texas and attended Texas A&M University in College Station. He was commissioned in December 1998 after earning a Bachelor of Science in Agricultural Business.
Upon completion of the Basic School and Ground Supply Officer Course, he reported to Combat Service Support Group-1 in Twentynine Palms, California. During this tour, he served as the Organic Supply Officer and Support Company Commander, deploying once in support of Operation IRAQI FREEDOM.
He was subsequently reassigned to Marine Aircraft Group 12 (MAG-12) in Iwakuni, Japan where he served as the Group Supply Officer. While assigned to MAG-12 he also served as the Headquarters Detachment Office-in-Charge for Exercise Cope North in Guam and Exercise Southern Frontier in Australia.
In 2004 Lieutenant Colonel Marksbury attended Expeditionary Warfare School and graduated in 2005. From 2005 until 2008 he served at Joint Advertising Market Research and Studies (JAMRS) working for the Under Secretary of Defense for Personnel and Readiness (P&R).
In July 2008 Lieutenant Colonel Marksbury reported to Blount Island Command in Jacksonville, Florida. He was assigned as the Operations Officer, Logistics Division and later was assigned as the Branch Head, Supply & Container Management Branch. He also served as the Technical Assistance Advisory Team Officer-in-Charge supporting downloads and backloads of ships during Exercise Cobra Gold/Freedom Banner and Baltic Operations (BALTOPS).
In 2011 Lieutenant Colonel Marksbury was transferred to I MEF (Forward) Camp Pendleton, California where he served as the I MEF (Forward) Supply Officer and deployed to Afghanistan in support of Operation ENDURING FREEDOM. Upon his return, he was assigned to 1st Supply Battalion where he served as the Supply Management Unit (SMU) Officer-in-Charge.
In 2014 Lieutenant Colonel Marksbury reported to United States Special Operations Command J4 where he served as the Deputy Branch Head J45. During this tour he deployed as the Commander, Joint SOF Support Detachment-Kuwait under United States Special Operations Command Central (SOCCENT). He also served as the Global Mission Support Center Chief of Operations for six months during this assignment.
In July 2017 Lieutenant Colonel Marksbury was assigned to Marine Corps Logistics Operations Group, Twentynine Palms, California where he served as the Exercise Department Head. As the Exercise Department Head he was responsible for the Logistic Staff Training Exercise/Battle Staff Training Exercise Program and the Expeditionary Logistics Seminar Program.
Lieutenant Colonel Marksbury is a graduate of the Marine Corps Expeditionary Warfare School, Joint Forces Staff College and the Command and Staff College Distance Education Program.