Lieutenant Colonel Walkup graduated from Southern Oregon University in 2007 and was commissioned the same year through the Platoon Leaders Course. After graduating from Infantry Officers Course in 2008, LtCol Walkup was assigned to 3d Battalion, 9th Marines from 2008 until 2011. With 3/9 he deployed to Al Anbar Province, Iraq in 2009, and then to Marjah, Afghanistan in 2010.
In 2011, LtCol Walkup reported to The School of Infantry-East in Camp Geiger, NC. He served as the Kilo Company Commander, Lima Company Commander, and as the Operations Officer of Marine Combat Training Battalion-East. During his time at the School of Infantry, LtCol Walkup completed non-resident Expeditionary Warfare School.
In April 2014, LtCol Walkup was assigned to 2nd Battalion, 8th Marines as Commanding Officer of Echo Company. In January 2015, Echo Company deployed to Naval Air Station Sigonella Italy in support of Special Purpose Marine Air Ground Task Force Crisis Response Africa. The company had a dual mission of providing a security force prepared to re-establish a diplomatic presence in Libya, as well as provide Security Cooperation Forces to various African partner nations. Following the deployment, LtCol Walkup joined the Select Marine Corps Reserve and moved back to his home state of Oregon.
In 2016, LtCol Walkup began his civilian career by taking a management position with the Oregon Department of Human Services, Aging and People with Disabilities. At the same time, he was serving the Marine Corps as a I MEF Individual Mobilization Augmentee. In 2019, LtCol Walkup deployed in support of Special Purpose Marine Air Ground Task Force Crisis Response Central Command and served as the Liaison Officer to Task Force 51/5th Marine Expeditionary Brigade.
LtCol Walkup left I MEF in 2022 and joined the Marine Corps Advisor Company Bravo in Concord CA. In the same year he graduated from Marine Corps Command and Staff College non-resident course. With MCAC-B, LtCol Walkup assumed the duties as Assistant Inspector Instructor, attended the Advanced Maneuver Warfare Course, and Summer Mountain Leaders Course. In 2024 LtCol Walkup participated in the annual multi-lateral Subject Matter Expert Exchange exercise Kamandag-8 in the Philippines.
LtCol Walkup's personal decorations include the Navy-Marine Corps Commendation Medal 2nd Award, and Combat Action Ribbon. He is married and has three kids.