Sergeant Major Douglas B. Schaefer entered the United States Marine Corps in 1989 and graduated from recruit training at Parris Island, South Carolina in July 1989. He was assigned to Camp Geiger, North Carolina where he attended the School of Infantry and received the Military Occupational Specialty 0352. He was meritoriously promoted to Lance Corporal.

In October 1989 Lance Corporal Schaefer was assigned to the Marine Corps Air Ground Combat Center, 29 Palms California, serving with TOW Company of 3rd, then 1st Tank Battalions. He was deployed to Okinawa, Japan and participated in Operations "Desert Shield" and "Desert Storm". In 1992 he received orders to Kaneohe Bay, Hawaii and served with 3rd Marine Regimental TOW Platoon, and transferred and deployed to Okinawa with Weapons Company, 1st Battalion, 3rd Marines.

In January 1996 Sergeant Schaefer received orders to Parris Island, South Carolina for Drill Instructor Duty. He was meritoriously promoted in January 1998 to Staff Sergeant. After his tour on the Drill Field, Staff Sergeant Schaefer was assigned to Lima Company, 3rd Battalion 8th Marines as a Rifle Platoon Sergeant where, with the 26th Marine Expeditionary Unit, participated in Operation "Shining Hope" in Albania, "Operation Joint Guardian" in Kosovo, and "Task Force Avid Response" in Turkey. Upon completion of the LF6F, Staff Sergeant Schaefer was reassigned to Weapons Company, 3rd Battalion, 8th Marines and held billets as Combined Anti-Armor Team Section Leader, Platoon Sergeant, and Platoon Commander. He deployed to Okinawa, Japan in December 2000.

August 2001 Staff Sergeant Schaefer was assigned to the Staff Non-Commissioned Officers Academy, Camp Lejeune, North Carolina, and served as a Faculty Adviser for the Sergeants Course & Advance Course. He was promoted to Gunnery Sergeant in September 2002.

Gunnery Sergeant Schaefer received orders to 2d Battalion, 8th Marines in August 2004. As the H&S Company GySgt, he deployed with the 26th Marine Expeditionary Unit, LF5F to the Mediterranean & Persian Gulf. In December 2005 he assumed the duties as Company First Sergeant for Company G, 2d Battalion, 8th Marines.

First Sergeant Schaefer transferred to Parris Island in March 2006 where he served as the Company First Sergeant for Company B, First Recruit Training Battalion, and Range Company, Weapons and Field Training Battalion. He was reassigned to 1st Battalion, 6th Marines in February 2009 as the H&S Company First Sergeant.

Sergeant Major Schaefer assumed the duties as Battalion Sergeant Major of 2d Battalion, 9th Marines, in February 2010. He deployed with “Hell in a Helmet” to Northern Marjah, Helmand Province, Afghanistan, returning in February, 2011.

His personal awards include the Bronze Star, Navy/Marine Corps Commendation Medal with two gold stars in lieu of third award, Navy/Marine Corps Achievement Medal with combat distinguishing device and Combat Action Ribbon with two gold stars in lieu of third award.