Sergeant Major Diaz was born and raised in Texas.  He enlisted in the Marine Corps in June 2003 and attended recruit training in Lima Company, 3rd Recruit Training Battalion, Marine Corps Recruit Depot San Diego, California.  In October 2003, he reported to the School of Infantry West, Camp Pendleton, California for Marine Combat Training.  He was then transferred to Field Radio Operator Course, Marine Corps Air Ground Combat Center, Twenty-nine Palms, California where he earned the Military Occupational Specialty (MOS) of 0621, Field Radio Operator. Sergeant Major Diaz was promoted to the rank of Lance Corporal in February 2004.
 
In March 2004, upon completion of school, Sergeant Major Diaz reported for duty to 3rd Force Service Support Group (FSSG), Camp Kinser, Okinawa, Japan.  He was assigned to Communications Company, Radio Platoon where he worked as a Field Radio Operator. In April 2004, he deployed to Thailand in support of Operation Cobra Gold. Upon return with Communications Company, Sergeant Major Diaz was attached to 31st Marine Expeditionary Unit (MEU). While on 31st  MEU, Sergeant Major Diaz deployed as a Field Radio Operator to Camp Fallujah, Iraq. He conducted combat actions in support of Operation Iraqi Freedom. Participation included a major role in Operation Phantom Fury, the clearing of Fallujah in November 2004. Sergeant Major Diaz was meritoriously promoted to the rank of Corporal in December 2004.  
 
In July 2005, Sergeant Major Diaz was assigned to 1st Marine Logistics Group (MLG), Combat Logistic Regiment 15, 1st Maintenance Battalion, Camp Pendleton, California where he served as a Field Radio Operator. In February 2006, he deployed as Electronic Key Management System (EKMS) Custodian for Combat Logistics Regiment 15, Camp Al Taqaddum, Iraq.  Sergeant Major Diaz was promoted to the rank of Sergeant in April 2006. In May 2007, he returned from the deployment and served as Field Radio Operator with 1st Marine Logistics Group (MLG), Combat Logistic Regiment 15 Radio Platoon. 
 
In July 2007, Sergeant Major Diaz was assigned to Expeditionary Warfare Training Group Pacific (EWTGPAC), Naval Amphibious Base, Coronado, California. He served as a Basic Instructor for the Intermediate and Advanced Radio Operator Course. He was deployed to Hawaii, Guam, and other Marine Corps bases in the Southern California area on multiple Mobile Training Teams (MTT). 
 
In July 2009, Sergeant Major Diaz was assigned to 3rd Battalion 11th Marines, Lima Battery, Marine Corps Air Ground Combat Center, Twenty-nine Palms, California where he served as a Radio Chief, and subsequently promoted to the rank of Staff Sergeant in November 2010. He was attached to Battalion Landing Team (BLT1/4) and deployed with the 31st MEU to Camp Hansen in Okinawa, Japan.
 
In July 2012, Sergeant Major Diaz reported to Marine Corps Recruit Depot San Diego, California for Drill Instructor Duty with class 4-12. Upon graduation in October 2012, Sergeant Major Diaz reported to Lima Company, 3rd Recruit Training Battalion.  Sergeant Major Diaz served as a Drill Instructor, Senior Drill Instructor, and Chief Drill Instructor for Lima Company. 
 
In November 2015, Sergeant Major Diaz was assigned to Marine Air Support Squadron 3, Marine Air Support Group 38, 3d Marine Aircraft Wing, Camp Pendleton, California where he served as the Communications and Electronics Company First Sergeant. Sergeant Major Diaz was promoted to the rank of Gunnery Sergeant in August 2016. 
 
In June 2017, Sergeant Major Diaz was assigned to 8th Communication Battalion, Charlie Company, II Marine Expeditionary Force, Camp Lejeune, North Carolina where he served as the Joint Task Force Enabler (JTFE) Staff Noncommissioned Officer-in-Charge and Transmissions System Chief. 
 
In April 2018, Sergeant Major Diaz was assigned to 22nd MEU,  II Marine Expeditionary Force, Camp Lejeune, North Carolina. Gunnery Sergeant Diaz deployed as the Transmissions System Chief for the Command Element aboard the USS Kearsarge to the 5th Fleet Area of Operation.
 
In July 2019, Sergeant Major Diaz returned to 8th Communication Battalion, Charlie Company, II Marine Expeditionary Force, Camp Lejeune, North Carolina where he served as the Charlie Company Gunnery Sergeant.
 
In June 2020, Sergeant Major Diaz was promoted to the rank of Fist Sergeant. Sergeant Major Diaz was assigned to 2d Battalion, 6th Marines, II Marine Division, Camp Lejeune, North Carolina where he served as the Echo Company First Sergeant.
 
In September 2021, Sergeant Major Diaz was assigned to 22nd MEU,  II Marine Expeditionary Force, Camp Lejeune, North Carolina. First Sergeant Diaz deployed as the Battalion Landing Team (BLT 2/6) Echo Company First Sergeant aboard the USS Arlington to the 6th Fleet Area of Operation.
 
In September 2022, Sergeant Major Diaz returned to 2d Battalion, 6th Marines, II Marine Division, Camp Lejeune, North Carolina where he served as the Echo Company First Sergeant.
 
In May 2023, Sergeant Major Diaz was assigned to 2d Supply Battalion, 2d Marine Logistics Group, Camp Lejeune, North Carolina where he served as the Ammunition Company First Sergeant.
 
On 15 November 2023, Sergeant Major Diaz was promoted to his current rank and assigned as the Battalion Sergeant Major at Combat Logistics Battalion 22, Combat Logistics Regiment 2, 2d Marine Logistics Group.