Sergeant Major Hernandez was born on 1 July 1985 in San Bernardino. He enlisted in the United States Marine Corps on 5 June 2005 and attended recruit training at Marine Corps Recruit Depot Parris Island. Upon graduation, he reported to the School of Infantry (SOI) East at Camp Geiger and was subsequently assigned to 3rd Battalion, 2nd Marines at Camp Lejeune.
 
While serving with 3rd Battalion, 2nd Marines, Sergeant Major Hernandez served as a SAW Gunner with 3rd Platoon, Lima Company. He deployed in support of Operation Iraqi Freedom in July 2006 and again in October 2007. During this period, he served as a Team Leader and was recognized as Marine of the Quarter in September 2007. He was promoted to Corporal in October 2007. In April 2009, Corporal Hernandez reenlisted and received orders to 1st Battalion, 1st Marines, where he served as a Squad Leader with Charlie Company. He was promoted to Sergeant in February 2010 and was subsequently selected by the Battalion Sergeant Major to serve in the Battalion S-3 as the Operations and Training Noncommissioned Officer. In this capacity, he managed battalion training and operations while serving as the Schools Noncommissioned Officer and overseeing the Body Composition and Military Appearance Programs.
 
In February 2011, Sergeant Hernandez deployed with the 13th Marine Expeditionary Unit aboard the USS Boxer, serving as the Battalion Watch Officer and Watch Chief. Upon returning from deployment in September 2011, he completed the Infantry Squad Leaders Course.
 
In July 2012, Sergeant Hernandez reported to Marine Corps Recruit Depot San Diego for Drill Instructor duty (Class 4-12). Upon completion of Drill Instructor School, he was assigned to Company A, 1st Recruit Training Battalion, where he served as a Drill Instructor, Experienced Drill Instructor, and Senior Drill Instructor for seven training cycles. In October 2014, he was hand-selected for reassignment to Headquarters Company, where he served as the Assistant Chief Drill Instructor for 1st Recruit Training Battalion's S-4 section.
 
Sergeant Major Hernandez was promoted to Staff Sergeant in October 2015 and assigned to 2nd Battalion, 2nd Marines. After graduating the Infantry Unit Leaders Course (2-16), he forward deployed to Okinawa, Japan, where he served as 3rd Platoon Sergeant with Company G.
 
In July 2017, Staff Sergeant Hernandez received orders to the School of Infantry East at Camp Lejeune. Upon graduating from Combat Instructor School, he was assigned to Infantry Training Battalion, Company C, where he served as an 0311 Platoon Sergeant, Weapons Platoon Sergeant, and Company Force Fitness Instructor.
 
On 2 June 2019, he was meritoriously promoted to Gunnery Sergeant and served as the 0300 Chief for the Battalion Training Instructor Group. During this assignment, he completed the SNCO Advanced Course and the Curriculum Developer Course.
 
In October 2020, Gunnery Sergeant Hernandez received orders to Rifle Company B, 1st Battalion, 24th Marines, 4th Marine Division, where he served as Company Gunnery Sergeant and Operations Chief.
 
Sergeant Major Hernandez was promoted to First Sergeant on 31 May 2023 and subsequently served as Company First Sergeant for Fox Company, 2nd Battalion, 4th Marines, 5th Marine Regiment. While assigned to 2nd Battalion, 4th Marines, he deployed to Okinawa, Japan, aboard the 31st Marine Expeditionary Unit.
 
In May 2025, he received orders to the School of Infantry (West), where he served as Company First Sergeant for Infantry Training Battalion, Company A. In July 2026, he received orders to Marine Corps Recruit Depot San Diego, where he currently serves as Sergeant Major for 3rd Recruit Training Battalion.
 
Sergeant Major Hernandez's personal decorations include the Navy and Marine Corps Commendation Medal (4th award), Navy and Marine Corps Achievement Medal (second award), Combat Action Ribbon, and the Military Outstanding Volunteer Service Medal.