Sergeant Major Ruiz assumed his current post as the 20th Sergeant Major of the Marine Corps on August 10, 2023.  A native of Sonora, Mexico, he enlisted in the United States Marine Corps on November 2, 1993, out of Buckeye, Arizona. He graduated from recruit training at Marine Corps Recruit Depot (MCRD) San Diego, California, in January 1994 and reported to Marine Combat Training at Camp Pendleton, California, shortly after. He was assigned as a Supply Warehouse Clerk as his military occupational specialty.

In May 1994, Sergeant Major Ruiz reported to Supply Company, 3d Supply Battalion, 3d Force Service Support Group, Okinawa, Japan. In May 1996 he received orders to Marine Corps Logistics Base, Barstow, California, and served as a supply warehouse clerk until October 1998 when he reported to Recruiting School at MCRD San Diego. Upon graduation he was assigned to Recruiting Station Los Angeles, 12th Marine Corps District. In October 2001, Sergeant Major Ruiz reported to Supply Company, 1st Supply Battalion, 1st Force Service Support Group. In January 2003 he deployed to Al Anbar Province, Iraq, with Equipment Reception Platoon and later with Combat Service Support Group-12 in support of Operation Iraqi Freedom. 

In April 2004, Sergeant Major Ruiz reported to Drill Instructor School at MCRD San Diego, orders he requested, and graduated in September 2004 with Class 4-04 as the class Honor Graduate and recipient of the Leadership Award. He was assigned to Company L, 3rd Recruit Training Battalion. In October 2006, Sergeant Major Ruiz was transferred to the Instructor Staff, Drill Instructor School, MCRD San Diego.  During this period he held the billets of Drill Master, Physical Training Instructor, and later the School's Chief Instructor. 

In April 2008, he reported to Supply Company, Combat Service Support Group-15. He served as Company Gunnery Sergeant until February 2009 when he reported to Company L, 3d Battalion, 4th Marine Regiment, to serve as the Company First Sergeant. He subsequently deployed to Helmand Province, Afghanistan, in support of Operation Enduring Freedom. Following the end of his first tour, Sergeant Major Ruiz was re-assigned to Headquarters and Service Company and completed a second tour to Afghanistan. 

In June 2012, Sergeant Major Ruiz received orders to Inspector-Instructor Staff, Sacramento, California, to serve as the Inspector-Instructor First Sergeant. In September 2013, upon his selection to Sergeant Major, he received orders to 3d Battalion, 5th Marine Regiment. He served as the Battalion Landing Team Sergeant Major, 31st Marine Expeditionary Unit, and as the Battalion Sergeant Major for Unit Deployment Program 16.1. 

In May 2016, Sergeant Major Ruiz received orders to 1st Combat Engineer Battalion and in December 2016 was re-assigned to Combat Logistics Regiment 17, 1st Marine Logistics Group. On December 7, 2018, Sergeant Major Ruiz was assigned as the 4th Marine Logistics Group Sergeant Major out of New Orleans, Louisiana.

In February 2021, Sergeant Major Ruiz assumed the duties U.S. Marine Corps Forces Reserve Sergeant Major. In May 2021, the Commander of Marine Forces Reserve assumed all authorities and responsibility of U.S. Marine Corps Forces South. As the result of the transfer of authority, Sergeant Major Ruiz served as both the MARFORRES and MARFORSOUTH Command Senior Enlisted Leader. 

Sergeant Major Ruiz's personal awards include the Legion of Merit with gold star, Bronze Star Medal with combat distinguishing device, Meritorious Service Medal with gold star, Navy and Marine Corps Commendation Medal with two gold stars, Navy and Marine Corps Achievement Medal with one gold star, and the Combat Action Ribbon with one gold star. He has earned a Bachelor's Degree in Organizational Management from the University of Arizona Global Campus.