Sergeant Major Cook assumed his post as the Command Senior Enlisted Leader (CSEL) for United States Indo-Pacific Command on 26 June 2025.

Prior to his current assignment, he served as the CSEL, MARFORPAC; CSEL, III Marine Expeditionary Force; CSEL, Marine Forces, Japan; CSEL, 3d Marine Division; CSEL, MARFORSOUTH; CSEL, Headquarters and Service Battalion, MARFORPAC; and CSEL Recruiting Station Milwaukee, WI.

Sergeant Major Eric D. Cook, a native of Ewing, IL, entered the Marine Corps in August of 1994. During his career, he has been assigned as a 60 mm mortar man with 2d Battalion, 2d Marines; 81 mm mortar section leader, 81 mm mortar Platoon Sergeant, and Mobile Assault Platoon Commander with 2d Battalion, 4th Marines; Company Gunnery Sergeant and Chief Instructor with Infantry Training Battalion and Instructor, Advanced Infantry Training Battalion, School of Infantry, West; Company First Sergeant, 3d Battalion, 1st Marines; and Inspector and Instructor First Sergeant, Military Police Company.

He has deployed with Battalion Landing Team 2d Battalion, 2d Marines, 22nd Marine Expeditionary Unit (Special Operations Capable) in 1996 and 1998; Battalion Landing Team 2d Battalion, 4th Marines, 31st Marine Expeditionary Unit (Special Operations Capable) from 2002 to 2003; Weapons Company, 2d Battalion, 4th Marines during Operation IRAQI FREEDOM in 2004; Battalion Landing Team 3d Battalion, 1st Marines, 31st Marine Expeditionary Unit (Special Operations Capable) from 2008 to 2009; and Company K, 3d Battalion, 1st Marines during Operation ENDURING FREEDOM (Afghanistan) in 2010.

Sergeant Major Cook’s personal awards include the Legion of Merit with three gold stars in lieu of fourth award, the Meritorious Service Medal with gold star in lieu of second award, the Navy & Marine Corps Commendation Medal with Combat Distinguishing Device and two gold stars in lieu of third award, the Navy and Marine Corps Achievement Medal with three gold Stars in lieu of fourth award, and the Combat Action Ribbon with gold star in lieu of second award.

Last Updated: 23 June 2025