Sergeant Major Dorsey enlisted in the Marine Corps out of California in 1998 and entered Recruit Training at Hotel Company, 2nd Battalion, MCRD San Diego, CA. Following Recruit Training, Sergeant Major Dorsey attended Marine Combat Training at Camp Pendleton, CA, where he was meritoriously promoted to Private First Class. Upon completion, he was assigned to Supply School at Camp Johnson, NC, where he earned the MOS of 3051, Supply Warehouse Clerk.

Sergeant Major Dorsey reported to Camp Lejeune, NC in August 1998 as a Warehouse Clerk with 2nd Supply Battalion, Supply Company, CTEP Platoon. In January 1999, Sergeant Major Dorsey was sent to H&S Company as the Commanding Officer's Driver. While serving in this billet, Sergeant Major Dorsey was promoted to Lance Corporal and meritoriously promoted to Corporal. In June of 1999, he attended Corporals Course where he was selected as one of the Distinguished Graduates.

In November 2001, he was reassigned as the Warehouse Chief with MSSG 24, 24th MEU. In 2002, he attended Sergeants Course and was selected as the recipient of the Gung Ho Award. During this tour, Sergeant Major Dorsey deployed and participated in numerous operations such as Operation KFOR Kosovo, Enduring Freedom, JTF HOA Djibouti Africa, and Iraqi Freedom.

In September 2003, Sergeant Major Dorsey received orders to MCRD San Diego for Drill Instructor School. Upon completion of Drill Instructor School, Sergeant Major Dorsey was assigned to Lima Company, 3rd Battalion where he served as a Drill Instructor and Senior Drill Instructor.  Upon selection to Staff Sergeant, he attended Career Course where he was the recipient of the Gung Ho Award.  In February of 2007, he was assigned to 2d Amphibious Assault Battalion as the Supply Warehouse Chief. He then attached to 1st Battalion, 9th Marines as the Headquarters Platoon Sergeant and Supply Chief for a deployment to Iraq. On 2 April 2010, he was selected as the MARFORCOM Meritorious Gunnery Sergeant. Sergeant Major Dorsey was then assigned to the Staff Noncommissioned Officer Academy as a Faculty Advisor for the Career Course until July 2012.

In August 2012, Sergeant Major Dorsey reported to MWSS 172, Okinawa, for duty as the Warehouse Chief and was later reassigned as the Aviation Operations Company First Sergeant upon his selection to First Sergeant in December 2013. As a frocked First Sergeant, he reported to Headquarters Company, Combat Logistics Regiment 3 where he deployed to Korea. Upon his return from Korea, he was hand selected and redeployed with the T-AKE 14-1 as the Company First Sergeant until September 2014. He was then reassigned to Motor Transportation Company A, 3d Transportation Support Battalion until April 2015. Sergeant Major Dorsey was then transferred to 9th Engineer Support Battalion from April 2015 to January 2016. In January 2016 he reported to Combat Assault Battalion, 3d Marine Division as the Company First Sergeant for Combat Engineer Company and Headquarters and Service Company until September 2017. Sergeant Major Dorsey then reported to Fox Company, 2d Recruit Training Battalion, Recruit Training Regiment, MCRD Parris Island SC, as the Fox Company First Sergeant until his promotion to Sergeant Major. Sergeant Major Dorsey assumed duty as the Sergeant Major of Recruiting Station Columbia, SC, from January 2019 until January 2022. Sergeant Major Dorsey assumed duty as the Barracks Sergeant Major for Marine Barracks, Washington, D.C. January 2022 until January 2024.

Sergeant Major Dorsey's personal awards include the Legion of Merit, Meritorious Service Medal, Navy and Marine Corps Commendation Medal with four gold stars in lieu of the 5th award, and Navy and Marine Corps Achievement Medal with three gold stars in lieu of the 4th award. He also received the General Gerald C. Thomas Award for Outstanding Leadership and Inspiration as well as the Dan Daly Leadership Award.