Sergeant Major Rivas was born September 9, 1984 in Fresno, California. First Sergeant Rivas enlisted in the Marine Corps in January 12, 2003 and attended recruit training at MCRD San Diego, California. Upon completion Sergeant Major Rivas received training at Marine Combat Training (MCT) Camp Pendleton, California. Following MCT, he reported to Motor Vehicle Operators Course at Fort Leonard Wood, and received the MOS 3533.
In November 2003, Sergeant Major Rivas reported to 1st MLG, Camp Pendleton, California. In January of 2004 First Sergeant Rivas deployed to Al-Taqadum, Iraq in support of Operation Iraqi Freedom as a machine gunner. In September of 2004 Sergeant Major Rivas returned from deployment and was assigned to Combat Logistics Battalion 1.
In August of 2005 Sergeant Major Rivas deployed again to Camp Fallujah, Iraqi ISO of Operation Iraqi Freedom as a LVS Operator. Sergeant Major Rivas returned in September of 2006. Upon return he was assigned to CLB 5.
In July of 2008 Sergeant Major Rivas deployed to Al Asad, Iraq ISO Operation Iraqi Freedom where he served as a Vehicle Recovery Operator. Sergeant Major Rivas returned in September of 2008 and was assigned to CLB 1.
In September of 2009, Sergeant Major Rivas deployed to Camp Dwyer, Afghanistan. Sergeant Major Rivas held the billet of Assistant Platoon Sergeant and Crew Serve Weapons Chief. Sergeant Major Rivas returned from deployment in March 2010.
In June of 2011, Sergeant Major Rivas deployed to Camp Dwyer, Afghanistan ISO Operation Moshtarak. He returned in March 2012.
In December of 2012, Sergeant Major Rivas reported to MWSS-374, MCAGCC 29 Palms, California. While there he served as a Company GySgt for Airfield Co.
In 2014, Sergeant Major Rivas deployed to Kuwait as part of Special MAGTF Crisis Response ISO operations ongoing in Iraq. Sergeant Major Rivas returned in April of 2015.
In July 2015, Sergeant Major Rivas reported Marine Corps Detachment, Fort Leonard Wood, Missouri. He served in multiple billets to include Master Instructor, SNCOIC, UVA and Company Gunnery Sergeant.
In June of 2019, Sergeant Major Rivas reported to Assault Amphibian School, as the Motor Transport Operations Officers. During his time he served as the S3 chief, SACO, and as the Logistics Officer for the Motor Transport Marines.
In January of 2022, Sergeant Major Rivas reported to Headquarters and Support Battalion, Marine Corps Installations West, Camp Pendleton, CA as Company First Sergeant for Bravo Company.
In January of 2026, Sergeant Major Rivas reported to 1/11, as the Senior Enlisted Advisor.
Sergeant Major Rivas' personal decorations include the Navy and Marine Corps Commendation Medal w/gold star, Navy and Marine Corps Achievement Medal w/4 star, Good Conduct Medal w 1 silver star and the Military Outstanding Volunteer Service Medal.