Lieutenant Colonel Gardenhire graduated from Texas A&M University in December 2007 with a B.S. in Biology. Upon graduation, he was commissioned as a Second Lieutenant in the Marine Corps through the Platoon Leaders Course and attended The Basic School in March 2008.
Following The Basic School, he completed Naval Aviator training at NAS Pensacola, NAS Corpus Christi, and NAS Meridian, earning his Wings of Gold in January 2011. He then trained in the AV-8B with Marine Attack Training Squadron (VMA) 203 at MCAS Cherry Point, NC. In December 2011, Captain Gardenhire was assigned to VMA-214 "Black Sheep" at MCAS Yuma, AZ. He served in multiple billets including Current Operations Officer, Powerline Officer in Charge, Assistant Aircraft Maintenance Officer, and Future Operations Officer. He deployed with the "Black Sheep" aboard the 13th MEU from August 2013 to April 2014.
In 2015, Captain Gardenhire attended Joint Terminal Attack Controller training and was assigned to 3d Light Armored Reconnaissance Battalion at Twenty Nine Palms, CA, serving as Air Officer and Assistant Operations Officer. In June 2016, he returned to VMA-214.
During his second tour with the "Black Sheep," he served as Quality Assurance Officer and graduated from the Weapons and Tactics Instructor (WTI) course in April 2017. He deployed with the 15th MEU as the AV-8B detachment WTI from July 2017 to January 2018, conducting combat operations in support of Operation Inherent Resolve. He was promoted to Major during this deployment.
Following the deployment, Major Gardenhire served as VMA-214 Pilot Training Officer and Operations Officer until July 2019. He then joined Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) as an Instructor Pilot and served as the AV-8B Division Head. In July 2022, he transferred to VMA-231 "Ace of Spades" at MCAS Cherry Point, serving as the Aircraft Maintenance Officer. He became Marine Aircraft Group 14 Operations Officer in June 2023 and was promoted to Lieutenant Colonel in September 2023.
LtCol Gardenhire was selected to command the Training Squadron 35 "Sting Rays" and transferred to NAS Corpus Christi in July 2024. He served as the USMC Training Command Liaison to CNATRA before assuming Executive Officer of VT-35 in August of 2025.
He has logged over 1,900 mishap-free flight hours and holds qualifications including Weapons and Tactics Instructor, Mission Commander, Air Combat Tactics Instructor, Low Altitude Tactics Instructor, and Night Systems Instructor. His personal awards include the Air Medal-Strike/Flight (Numeral 1), Navy/Marine Corps Commendation Medal (3 Gold Stars), and Navy/Marine Corps Achievement Medal (Gold Star).