Joshua Grayek is a CWO4, Infantry Weapons Officer colloquially called a Marine Gunner. The Marine Gunner is a CWO specifically trained in the employment and training of infantry battalion organic weapons, gear and assigned personnel, while serving as a special staff officer employed as the principal advisor to commanders at all levels. They assist in the development of training and employment plans designed to ensure mission essential task (MET) compliance and mission readiness.

Gunner Grayek enlisted into the Marine Corps in 1998 and has served in a myriad of ground combat element units and instructor billets. Gunner Grayek is currently serving as the Director of Marksmanship for the USMC. His areas of responsibility include managing the Marine Corps Combat Marksmanship Program which covers all facets of small arms combat marksmanship for marksmanship doctrine, training, competition, equipment, and weapons qualifications for the Service.