LtCol Gillett was commissioned as a 2nd Lieutenant in January 1998 through the Platoon Leaders Course officer program. After completing The Basic School in Quantico, Virginia, he was selected as a Marine Artillery Officer and attended Artillery Officer Basic course in Ft. Sill, Oklahoma, where he earned the 0802 MOS. After Artillery School, his first orders were to Alpha Battery, 1st Battalion, 11th Marines at Camp Pendleton, California. While with Alpha Battery, he served as the Fire Direction Officer, Forward Observer and Liaison Officer and deployed as a part of the 13th Marine Expeditionary Unit (Special Operations Capable) and responded during Operations BOLD SAMARATIN (East Timor), and DETERMINED RESPONSE (Aden, Yemen). He then served as the Battalion Fire Direction Officer for 1/11and as the Executive Officer for Headquarters Battery, 11th Marines.
After his initial tour on active duty and promotion to Captain, he transferred to the Selected Marine Corps Reserves and joined November Battery, 5th Battalion, 14th Marines in Pico Rivera, California in April 2002 where he served as the Fire Direction Officer and then as the Battery Commander. As Commander of November Battery, Captain Gillett deployed with 5/14 as a provisional Military Police Battalion in September 2005 in support of Operation IRAQI FREEDOM 4-6 in Camp Fallujah, Iraq. In addition to his duties as Battery Commander, Captain Gillett served as Company Commander for the Area Security/Force Protection Company.
Upon return from deployment, Captain Gillett transferred to the Peacetime/Wartime Support Team (PWST) with Mobilization Command in May 2007 where he planned and executed several mobilization events for Individual Ready Reserve Marines. After serving as a PWST OIC for three years, Major Gillett returned to 5/14 in 2010 as the Operations Officer and then the Executive Officer. After his last tour at 5/14, Major Gillett served with the First Marine Expeditionary Force (I MEF) in the G3 Fires and Effects Coordination Center as a Fire Support Officer where he was promoted to Lieutenant Colonel and supported exercises such as MEFEX and a multinational exercise, DAWN BLITZ 15. Lieutenant Colonel Gillett holds a Bachelors of Science Degree in Civil Engineering and is a graduate of Command and Staff College Distant Education Program.