Sergeant Major Darnell T. Richardson enlisted in the United States Marine Corps on 18 February 1992 from South Bound Brook, New Jersey and attended recruit training at Company I, 3d Recruit Training Battalion, MCRD, Parris Island, South Carolina and graduated as the Company Honor man. Upon graduation, Private First Class Richardson attended Marine Combat Training at Camp Geiger following his MOS school at Personnel Administration School and was assigned the MOS of 0131. After completing training, Private First Class Richardson was assigned to MWHS-2, MCAS, Cherry Point, North Carolina where he served as a unit diary clerk from September 1992 until May of 1994.
In June 1994, Lance Corporal Richardson was assigned to HQBN, HQMC, Henderson Hall (MMSR-7) in Arlington, Virginia where he served as a unit diary clerk for Separations and Retirement Branch until June 1996.
In July 1996, Corporal Richardson was assigned to Marine Security Guard Battalion (State Department), Quantico, Virginia where he served as the assistant unit diary chief and promotions NCOIC. Corporal Richardson was promoted to Sergeant and served as the Unit Diary Chief and Platoon Sergeant until May 2000.
In June 2000, Sergeant Richardson requested and received orders to Drill Instructor School, MCRD, San Diego, California. Upon completion of school, he was assigned to Company A, 1st Recruit Training Battalion, and was the recipient of the Gunnery Sergeant Nichol's award for the best new Drill Instructor during his first cycle. He served as a Drill Instructor and Senior Drill Instructor. In October 2002, Staff Sergeant Richardson was selected to serve as an Instructor at Drill Instructor School, where he served as the Physical Fitness, Martial Arts, CPR, and Squad Instructor until October 2003.
In November 2003, Staff Sergeant Richardson was transferred to Consolidated Personnel Administration Center, Headquarters and Service Battalion, MCRD San Diego, California where he served as the Personnel Administration Chief as well as an Inspector for the Inspector General, WRR, until July 2005.
In August 2005, Staff Sergeant Richardson was assigned to 3d Intelligence Battalion, III MHG, Okinawa, Japan where he served as the Battalion Adjutant. He was transferred in January 2007 to serve as the Adjutant Chief, III MHG.
In March 2007, Gunnery Sergeant Richardson was transferred to 4th Marines, 3d Marine Division and attached to Embedded Training Team (3-4) as the G-1 Mentor to the 201st Corps ANA as well as the G-1 Chief (fwd) for 7 ETT's. He was deployed to Afghanistan from July 2007 until April 2008. Upon return, Gunnery Sergeant Richardson was transferred to IPAC, MCB Camp Butler, Okinawa, Japan where he served as the Customer Services SNCOIC until May 2009.
In June 2009, First Sergeant Richardson was frocked and was assigned to 1st Battalion, 10th Marines, Camp Lejeune, NC where he served as First Sergeant for Battery B. In February 2010, he was transferred to BLT 1/9, 24th MEU, where he was deployed aboard the USS Mesa-Verde to the Mediterranean Sea, Persian Gulf, and Indian Ocean. Following OPERATION UNIFIED RESPONSE in Haiti, he conducted sustainment training exercises in Djibouti, Kuwait, EXERCISE SEA SOLDIER in Oman, and EXERCISE INFINITE MOONLIGHT in Jordan from May 2009 until June 2010.
In September 2010, First Sergeant Richardson was assigned to 2d Battalion, 10th Marines where he served as First Sergeant for Headquarters Battery until August 2011. In September 2011, he was transferred back to 1st Battalion, 10th Marines and was assigned as the First Sergeant for Headquarters Battery. From October 2011 until December 2011 he assumed the duties as the Battalion Sergeant Major (Acting). First Sergeant Richardson continued to serve as First Sergeant for Headquarters Battery until July 2012.
In July 2012, First Sergeant Richardson was assigned to Infantry Training Battalion, School of Infantry-East as First Sergeant for Charlie Company until March 2013. In March 2013, he assumed his duties as the First Sergeant for Headquarters and Service Company, Headquarters and Support Battalion, School of Infantry-East. In June 2014, Sergeant Major Richardson assumed his post as the MALS-12 Sergeant Major, MAG-12, 1st MAW, Iwakuni, Japan, until February 12, 2016. On February 26, 2016, he was assigned to Headquarters and Headquarters Squadron, MCAS Iwakuni, where he serves as the squadron Sergeant Major.
Sergeant Major Richardson's personal awards include the Meritorious Service Medal (gold star in lieu of second award), Navy/Marine Corps Commendation Medal (silver star in lieu of sixth award), Navy/Marine Corps Achievement Medal, and the Humanitarian Service Medal.