First Sergeant Cassell is a native of Dayton, Ohio. He enlisted in the Marine Corps on July 9, 2007, and attended recruit training at Mike Company, 3rd Recruit Training Battalion, Marine Corps Recruit Depot Parris Island.
In October 2007, First Sergeant Cassell attended Marine Combat Training, School of Infantry at Camp Geiger. Upon completion of Marine Combat Training, he attended Marine Artillery Scout Observer School in Fort Sill, Oklahoma. He then conducted follow on training at Fire Support Man Course at Naval Amphibious Base Coronado. He was assigned the military occupational specialty 0861, Fire Support Man.
First Sergeant Cassell reported to Bravo Battery, 1st Battalion, 12th Marines in Kaneohe Bay, Hawaii in April of 2008. While a member of 1st Battalion, 12th Marines, he was promoted to the rank of Lance Corporal and served as a scout observer. In September of 2008, he deployed to Iraq in support of Operation Iraqi Freedom. In November of 2008 he was promoted to the rank of Corporal, where he now served as vehicle gunner. In June of 2010, he was promoted to the rank of Sergeant.
In September of 2010, First Sergeant Cassell reported for duty as a Marine Artillery Scout Observer Instructor at Fort Sill, Oklahoma.
In March of 2013, First Sergeant Cassell reported to the Basic Recruiter Course at Marine Corps Recruit Depot, San Diego. Upon completion, he reported to Recruiting Station Charleston, West Virginia. He was promoted to the rank of Staff Sergeant in June of 2014. First Sergeant Cassell served as a canvassing recruiter until 2015 and then became the Recruiting Substation Xenia, Ohio, Staff Noncommissioned Officer in Charge. First Sergeant Cassell completed a successful tour of Recruiting Duty in May of 2016.
First Sergeant Cassell reported to 2d Air Naval Gunfire Liaison Company, II MEF in July of 2016 and was assigned to 1st Brigade Platoon, Supporting Arms Liaison Team Alpha where he served as the Supporting Arms Liaison Team Chief. He deployed to Bagram, Afghanistan from April to October 2018 in support of the Georgian Deployment Program. He was promoted to the current rank of Gunnery Sergeant in August of 2018.
In December of 2018, First Sergeant Cassell conducted PCA orders to 2nd Battalion, 10th Marines.
In January of 2019, First Sergeant Cassell conducted PCA orders to 1st Battalion, 10th Marines, to execute the billet of 2d Battalion, 8th Marines Battalion Fire Support Officer. He deployed on the 26th MEU with Battalion Landing Team 2/8 from December 2019 through July 2020. Upon completion of the deployment, First Sergeant Cassell returned to 1st Battalion, 10th Marines.
First Sergeant Cassell executed orders, March of 2021 to Headquarters Marine Corps, DC Plans, Policies & Operations, Current Operations Branch to serve as a Watch Team Chief in the Marine Corps Operations Center.
In May 2024, First Sergeant Cassell executed orders to Site Support - Milwaukee, Wisconsin, and is currently serving as Inspector-Instructor First Sergeant, Company F, 2d Battalion, 24th Marines, 23rd Marine Regiment.
First Sergeant Cassell's personal awards include the Navy and Marine Corps Commendation Medal with one gold star, Navy and Marine Corps Achievement Medal with one gold star and "C" device.