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, he reported to the School of Infantry where he earned the MOS 0311. Upon graduation in July 1997, he reported to Golf Company, 2d Battalion, 8th Marines.
In April 2000, he was promoted to the rank of Sergeant and reported to Marine Corps Combat Service Support Schools, to conduct a lateral move to MOS 3043, Supply Administration. In March 2002, Sergeant Mendez was transferred to Marine Corps Embassy Security Command, Quantico, Virginia. During this assignment, he was promoted to the rank of Staff Sergeant.
In December 2004, Staff Sergeant Mendez transferred to 2d Battalion, 8th Marines, Headquarters and Service Company. In August 2007, Staff Sergeant Mendez transferred to Marine Corps Combat Service Support Schools where he served as an instructor. In December 2008, Staff Sergeant Mendez was promoted to the rank of Gunnery Sergeant and transferred to the 22d Marine Expeditionary Unit.
In July 2012, Gunnery Sergeant Mendez was transferred to the Staff Noncommissioned Officer Academy, Camp Johnson. He was assigned as the Chief Faculty Advisor for Sergeant's Course. In January 2014, he was promoted to First Sergeant and received orders to Golf Company, 2d Battalion, 8th Marines.
In August 2015, First Sergeant Mendez was transferred to 9th Communication Battalion where he served as a Company First Sergeant. In January 2018, First Sergeant Mendez was promoted to the rank of Sergeant Major and was transferred to I Marine Expeditionary Force Support Battalion, 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 the post as the 2nd Marine Expeditionary Brigade Senior Enlisted Leader. In April 2024 he assumed his current post as the 2d Marine Division Senior Enlisted Leader.
Sergeant Major Mendez's personal decorations include the Legion of Merit, 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.