Sergeant Major Mendez is a native of Brooklyn, New York, and enlisted in the Marine Corps in January 1997. Upon completion of recruit training at MCRD Parris Island, South Carolina, Private First Class Mendez reported to the School of Infantry where he earned the MOS 0311 and was meritoriously promoted to the rank of Lance Corporal. Upon graduation in July 1997, Lance Corporal Mendez reported to Golf Company, 2nd Battalion, 8th Marines, where he served as an Automatic Rifleman. He was then meritoriously promoted to the rank of Corporal in December 1999.
In April 2000, he was promoted to the rank of Sergeant and then reported to Ground Supply School, Marine Corps Combat Service Support School, to conduct a lateral move to MOS 3043, Supply Administration. Upon completion, he deployed with 2nd Battalion, 8th Marine, on the 24th Marine Expeditionary Unit.
In March 2002, Sergeant Mendez was transferred to Marine Corps Embassy Security Command, Quantico, Virginia, where he served as the Command Supply Chief and Battalion Color Sergeant. During his assignment, he was promoted to the rank of Staff Sergeant in November 2004.
In December 2004, Staff Sergeant Mendez transferred back to 2nd Battalion, 8th Marines, where he served as the Battalion Supply Chief and Headquarters and Service Company Gunnery Sergeant. In August 2007, Staff Sergeant Mendez then transferred to Ground Supply School where he served as an instructor. In December 2008, Staff Sergeant Mendez was promoted to the rank of Gunnery Sergeant and subsequently transferred to the 22nd Marine Expeditionary Unit where he served as the Marine Expeditionary Unit Supply Chief and the Forward Command Element Staff Noncommissioned Officer-in-Charge.
In July 2012, Gunnery Sergeant Mendez was assigned as a Faculty Advisor at the Staff Noncommissioned Officer Academy, Camp Johnson, Camp Lejeune, North Carolina, and subsequent Chief Faculty Advisor for Sergeant's Course. In January 2014, he was promoted to First Sergeant and received orders to Golf Company, 2nd Battalion, 8th Marines, where he served as the Company First Sergeant.
In August 2015, First Sergeant Mendez was transferred to 9th Communication Battalion where he served as the Company First Sergeant for both Headquarters Company and Alpha Company. In January 2018, First Sergeant Mendez was promoted to the rank of Sergeant Major and was transferred to I Marine Expeditionary Force Support Battalion, I Marine Expeditionary Force, to serve as the Command Senior Enlisted Leader.
In November 2019, he served as the 2d Reconnaissance Battalion Senior Enlisted Leader; and in April 2022, he assumed the post as the Regimental Senior Enlisted Leader for Combat Logistics Regiment 2. In June 2023, he assumed his current post as the 2nd Marine Expeditionary Brigade Senior Enlisted Leader.
Sergeant Major Mendez's personal decorations include the Meritorious Service Medal (third award), Navy and Marine Corps Commendation Medal (sixth award), Navy and Marine Corps Achievement Medal (fourth award), and the Combat Action Ribbon.