Colonel Petkus is originally from Milford, Michigan. In 2004, he graduated from The United States Naval Academy with a Bachelor of Science in Chemistry and was commissioned into the United States Marine Corps. After attending The Basic School, he completed Ground Supply Officer Course in Camp Johnson, North Carolina. Colonel Petkus then reported to 3rd Battalion, 6th Marines in Camp Lejeune, North Carolina as the Battalion Supply Officer. In this capacity, he deployed in support of Operation Iraqi Freedom to Al Qaim, Iraq in 2005 and Habbaniyah, Iraq in 2007.
In 2007, Colonel Petkus reported to 10th Marine Regiment. He served as the Regimental Supply Officer and S-4A until executing orders to Recruiting Station San Diego in 2008.
From 2008 to 2011, Colonel Petkus served as the Officer Selection Officer for Officer Selection Team San Diego. Following this tour, he attended Expeditionary Warfare School in Quantico, Virginia. After graduating in 2012, he executed orders to 3d Supply Battalion in Okinawa, Japan.
Upon arrival at 3d Supply Battalion, Colonel Petkus assumed the billet of Operations Officer. From 2013 to 2015, he served as the Supply Management Unit Officer in Charge and Supply Company Commander. During his time with the battalion, Colonel Petkus participated in exercises Balikatan (Philippines), Freedom Banner (Republic of Korea), and Cobra Gold (Thailand). During this time, he also earned a Master of Business Administration from the University of North Carolina Kenan-Flagler Business School.
From 2015 to 2016, Colonel Petkus attended Army Command and General Staff College in Fort Leavenworth, Kansas. After graduating, he served as the inaugural commander of Recruiting Station Riverside in Riverside, California. Following command in 2019, he reported to 3d Marine Aircraft Wing (MAW) in San Diego, California.
While with 3d MAW, Colonel Petkus served in the G-4 holding billets of Materiel Readiness Branch Officer in Charge, Operations and Plans Officer, and Deputy Assistant Chief of Staff. In June 2021, Colonel Petkus assumed command of 1st Maintenance Battalion. He relinquished command in June 2023 and reported to the United States Naval War College.
Colonel Petkus graduated from the Naval War College in June 2024 and earned a Master of Arts in National Security and Strategic Studies. He then reported to United States Forces Korea where he served as the J4 Joint Plans and Exercises Chief then Deputy J5.
In June 2026, Colonel Petkus assumed command of 4th Marine Corps district. He is married to the former Breann Castiglione of Milford, Michigan. They have three children: Luke, Calla, and Kane.