Sergeant Major Trevor Jennings was born in Brooklyn, New York. He enlisted in the Marine Corps in October 1997. Sergeant Major Jennings was meritoriously promoted to Private First Class upon graduating from boot camp for receiving the title of Platoon Honor Graduate. Sergeant Major Jennings attended and completed Marine Corps Combat Training. Sergeant Major Jennings was promoted to Lance Corporal in September 1998 and graduated from Marine Corps Communication Electronics School in November 1998 as a Ground Radio Repairman.
Sergeant Major Jennings checked into Marine Wing Support Squadron 274 as a Ground Radio Repairman in January 1999. In February 1999 Sergeant Major Jennings deployed in support of Battle Griffin '99 in Norway. Sergeant Major Jennings was meritoriously promoted to Corporal in March 2000. He again deployed in direct support of two Combined Arms Training Exercises in Twentynine Palms, California in 2001. Sergeant Major Jennings was promoted to Sergeant in October 2001.
In November 2002, Sergeant Major Jennings checked into Marine Forces Atlantic G-6 as the Maintenance Chief. He completed Sergeants Course in October 2003. In August 2004 Sergeant Major Jennings checked into Marine Corps Communication Electronics School as a student and received the Military Occupational Specialty of Communications Maintenance Technician. Sergeant Jennings was promoted to Staff Sergeant in February 2005 and checked into 1st Battalion, 3rd Marines in May 2005. In December 2005 Sergeant Major Jennings deployed to Jalalabad, Afghanistan as Battalion Communications Maintenance Chief in support of Operation Enduring Freedom. In August 2006 Sergeant Major Jennings attended the Staff Non-Commissioned Officer Career Course. In February 2007 Sergeant Major Jennings deployed to Haditha, Iraq in support of Operation Iraqi Freedom with 1/3.
In February 2008 Sergeant Major Jennings checked into Marine Corps Communication Electronics School to assume responsibilities as a formal school instructor. While at MCCES, Sergeant Major Jennings served as Class Commander, Block Lead Instructor, Chief Instructor, Section Gunnery Sergeant and MAT platoon SNCOIC. In August 2010 Staff Sergeant Jennings was promoted to Gunnery Sergeant.
In October 2011 Sergeant Major Jennings assumed the assignment as the Communications Maintenance Chief with 1st Marine Raider Support Battalion. On this assignment he earned the additional MOS of Special Operations Capable Communicator. In 2014, Sergeant Major Jennings deployed to Afghanistan with 1st Marine Raider Battalion to serve as the Radio Chief for Special Operations Task Force West 81 in support of Operation Enduring Freedom. Additional duties he served as the SOTF Commander Radio Operator. Sergeant Major Jennings served as an advisor to the 2nd SOK G-6 Commander of the Afghanistan Commandos. In April 2015 Sergeant Major Jennings checked into Marine Combat Instructor School at School of Infantry West. Upon graduation, in June 2015, he reported as a 0913 to Hotel Company, Marine Combat Training Battalion, to serve his duties as a Marine Combat Instructor at SOI West.
In January 2016, Sergeant Major Jennings was frocked to First Sergeant and assumed the billet at Hotel Company and Golf Company at MCT. In June 2016, Sergeant Major Jennings assumed the billet of Company First Sergeant for Lima Company and H&S Company, Headquarters and Support Battalion until executing orders to III MIG in January 2018. In January of 2018, Sergeant Major Jennings assumed duties in H&S Company and Support Company, III MEF Support Battalion, III MIG until May 2019. He then served as the First Sergeant for Truck Company, Headquarters Battalion, 3rd Marine Division until November 2019. In November 2019 he was frocked to his current rank and assumed the position with 3d Transportation Support Battalion as the Battalion Sergeant Major until April 2021. In May 2021 he assumed the office of Squadron Sergeant Major for Marine Fighter Attack Squadron 121.
Sergeant Major Jennings received his Bachelor of Arts in Military Leadership, Master of Arts in Criminal Justice from Excelsior College and completed Expeditionary Warfare School.
Sergeant Major Jennings has received the Meritorious Service Medal, Navy and Marine Corps Commendation Medal gold star in lieu of sixth award, Navy and Marine Corps Achievement Medal, Marine Corps Outstanding Voluntary Service Medal.
Sergeant Major Jennings is married to the former Jaymie-Summer Teano.