Sergeant Major John L. Estrada enlisted on 5 September 1973 and attended recruit training at Marine Corps Recruit Depot, Parris Island, SC. After completing F-4 aircraft maintenance schools at Naval Air Station (NAS), Memphis, TN and Marine Corps Air Station (MCAS), Cherry Point, NC, Private First Class Estrada was assigned to Marine Fighter Attack Squadron 451 at MCAS Beaufort, SC in March, 1974.
In December 1974, Lance Corporal Estrada was transferred to Marine Fighter Attack Squadron 232, 1st Marine Aircraft Wing, Iwakuni, Japan. He was meritoriously promoted to Corporal in March, 1975.
In February, 1976, Sergeant Estrada served with Marine Fighter Attack Training Squadron 101, MCAS Yuma, AZ. In September, 1977, he transferred to Marine Fighter Attack Squadron 314, MCAS El Toro, CA. Reassigned to Marine Fighter Attack Squadron 323 in December, 1978, he deployed with the squadron in November 1979 for 7 months aboard the aircraft carrier USS Coral Sea to the Western Pacific and Arabian Gulf. In June, 1980, Staff Sergeant Estrada transferred to Marine Reserve Fighter Attack Squadron 321, Marine Aircraft Group 41, Detachment "A" at Andrews AFB, Maryland.
In August, 1982, Staff Sergeant Estrada was ordered to Drill Instructor Duty at Marine Corps Recruit Depot, San Diego, CA where he served with Kilo Company, 3d Recruit Training Battalion. He was meritoriously promoted to Gunnery Sergeant in January, 1984. In October 1984, Gunnery Sergeant Estrada returned to MCAS Beaufort, SC for duty with Marine Fighter Attack Squadron 251 as the Noncommissioned Officer in Charge of the Airframes Division. In November 1985, he was reassigned to Marine Fighter Attack Squadron 451 and deployed to the Western Pacific from January to July 1986 under the Unit Deployment Program. From January to March 1987, Gunnery Sergeant Estrada attended aircraft maintenance schools at Naval Air Stations Cecil Field and Jacksonville, FL retraining as an FA-18 Hydraulic/Structural Mechanic.
In October 1987, Gunnery Sergeant Estrada returned to Drill Instructor duty, this time at MCRD Parris Island, SC. He served as Series Chief Drill Instructor with India Company, 3d Recruit Training Battalion and subsequently as Standing Operations Procedures Instructor and Drill Master at Drill Instructor School until his promotion to First Sergeant in October 1990.
From December 1990 to March 1995, First Sergeant Estrada served as First Sergeant for Intelligence Company, 3d Surveillance Reconnaissance and Intelligence Group, Camp Hansen, Okinawa, Japan; Marine Security Force Company, Norfolk, VA; Electronics Maintenance Company, 1st Maintenance Battalion, 1st Force Service Support Group, Camp Pendleton, CA; and Alpha Company, 1st Light Armored Reconnaissance Battalion, 1st Marine Division, Camp Pendleton, CA.
From March 1995 to May 1998, Sergeant Major Estrada served as Sergeant Major for 2d Battalion, 1st Marines, BLT 2/1, 1st Marine Division, Camp Pendleton, CA; and deployed with the 11th Marine Expeditionary Unit (SOC) and 15th Marine Expeditionary Unit (SOC) to the Western Pacific and the Arabian Gulf.
In May, 1998, Sergeant Major Estrada assumed the duties as Sergeant Major for Recruiting Station Sacramento, CA in the 12th Marine Corps District, Western Recruiting Region. From April 2000 to October 2001, Sergeant Major Estrada was assigned as Sergeant Major, Recruit Training Regiment, MCRD Parris Island, SC.
From December 2001 to May 2003, Sergeant Major Estrada served as the Sergeant Major, 3d Marine Aircraft Wing. During this assignment, he was forward deployed and participated in Operation Southern Watch and Operation Iraqi Freedom.
Sergeant Major Estrada assumed his current post as the 15th Sergeant Major of the Marine Corps on 26 June 2003.