Sergeant Major Macias graduated recruit training at Marine Corps Recruit Depot, San Diego in November of 1995. Private Macias was attached to Marine Combat Training Battalion for follow on training and was assigned the MOS of 3531: Motor Transport Operator. After completing Motor Transportation School in March of 1996, he obtained the rank of Private First Class and was then assigned to Third Medical Battalion, Third Force Service Support Group in Okinawa, Japan where he was promoted to the rank of Lance Corporal. Soon after his promotion, Lance Corporal Macias was assigned to H&S Company, Motor Transport Platoon where he was promoted meritoriously to the rank of Corporal.
In March of 1997, Corporal Macias was transferred to Weapons and Field Training Battalion at Marine Corps Recruit Depot, Parris Island, South Carolina, for duty as a Field Training Instructor. There, he served as an instructor for Basic Warrior Training and was a Crucible Event Leader where he was then promoted to the rank of Sergeant.
In June 2000, Sergeant Macias completed Drill Instructor School and Marine Combat Instructor of Water Survival School. Sergeant Macias was then assigned to Mike Company, Third Recruit Training Battalion as a drill instructor. During his tour on Parris Island, Sergeant Macias was a Drill Instructor, Senior Drill Instructor, Chief Drill Instructor, and Marine Combat Instructor Trainer of Water Survival Team Leader. He was selected as the Drill Instructor of the Quarter, Senior Drill Instructor of the Quarter twice, and was meritoriously promoted to the rank of Staff Sergeant.
In August 2004, Staff Sergeant Macias transferred to Marine Wing Support Squadron (MWSS) 273, Marine Wing Support Group 27, MCAS Beaufort, South Carolina. Staff Sergeant Macias deployed in support of Operation Iraqi Freedom in 2005 and again in 2006. During this time he was promoted to the rank of Gunnery Sergeant.
In April 2007, Gunnery Sergeant Macias was transferred to the University of Notre Dame, Naval Reserve Officer Training Program to serve as the Assistant Marine Officer Instructor. During this tour he was named Assistant Marine Officer Instructor of the Year for the North Eastern Region and was frocked to the rank of First Sergeant.
In July 2010, First Sergeant Macias was transferred to General Support Maintenance Company, 4th Maintenance Battalion, 4th Marine Logistics Group where he served as the Inspector-Instructor First Sergeant. In January 2013, he was reassigned as the Bravo Company First Sergeant, First Recruit Training Battalion, Recruit Training Regiment, Parris Island, South Carolina.
In June of 2015, Sergeant Major Macias was assigned to 2d Battalion, 7th Marines where he deployed with the Special Purpose Marine Air Ground Task Force, Crisis Response, Central Command as the Ground Combat Element Sergeant Major in support of Operation Inherent Resolve. In February of 2017, Sergeant Major Macias was reassigned as the Battalion Sergeant Major for 1st Tank Battalion.
In September of 2018, Sergeant Major Macias was assigned to his current billet as the Headquarters and Service Battalion Sergeant Major for Marine Corps Base Quantico.
His personal decorations include the Meritorious Service Medal, Navy/Marine Corps Commendation Medal with 4 gold stars and the Navy/Marine Corps Achievement Medal with 1 Gold Star.