ENLISTED Often referred to as the backbone of the Corps, enlisted Marines with pay grades E-1 through E-3 are Junior Enlisted. E-4 and E-5 are non-commissioned officers (NCOs). Staff NCOs are career Marines serving in grades E-6 through E-9 (SNCOs). Together they are responsible to the commanding officer for the welfare, morale, discipline, and efficiency of Marines in their charge. The ranks of E-8 and E-9 each have two ranks per pay grade, with distinct responsibilities. Gunnery sergeants (E-7) indicate their preferred promotional track on their annual evaluations. First sergeants (E-8) and sergeants major (E-9) serve as senior enlisted advisors assisting the commanding officer in matters of discipline, administration, and the morale and welfare of the unit. First sergeants serve as the senior enlisted Marine in a company, battery, or other unit at similar echelon, while sergeants major serve the same role in battalions, squadrons, or larger units. Master sergeants (E-8) and master gunnery sergeants (E-9) provide technical leadership as occupational specialists in their specific MOS.
The sergeant major of the Marine Corps is the senior enlisted Marine of the entire Marine Corps, personally selected by the commandant. The sergeant major of the Marine Corps and the Marine gunner are the only billets which rate modified rank insignia in place of traditional rank insignia.
ENLISTED CORPSMAN HR: Hospitalman Recruit (E-1) HA: Hospitalman Apprentice (E-2) HN: Hospitalman (E-3) HM3: Hospital Corpsman Third Class (E-4) HM2: Hospital Corpsman Second Class (E-5) HM1: Hospital Corpsman First Class (E-6) HMC: Chief Hospital Corpsman (E-7) HMCS: Senior Chief Hospital Corpsman (E-8) HMCM: Master Chief Hospital Corpsman (E-9)
WARRANT OFFICER Warrant officers specialize in their respective fields, providing leadership and training to the Marines in their military occupational specialty. A warrant is approved by the secretary of the Navy for a sergeant (E-5) or staff non-commissioned officer (E-6 to E-9) to be appointed a warrant officer. Warrant officers become commissioned officers at the rank of Chief Warrant Officer 2, though they will generally serve as technical advisors, providing expertise to commands and organizations in their field.
A chief warrant officer serving as an infantry weapons officer also carries the title, "Marine Gunner", which does not replace his rank. However, a Marine Gunner replaces the chief warrant officer insignia on the left collar with a bursting bomb insignia.
OFFICER Commissioned officers are college graduates who have earned and accepted an appointment issued in the name of the president of the United States. Their commission gives them the responsibility of leading Marines as they defend the Constitution of the United States. Commissioned officer ranks are further subdivided into generals, field-grade, and company-grade officers. The commandant of the Marine Corps and the assistant commandant of the Marine Corps are four-star ranks.
Company Grade Officers (O-1 through O-4): O-2 is generally automatic after two years as an O-1. O-3s act as Company Commanders for 62 to 190 Marines, and are in charge of the tactical and everyday operations of their company.
Pay Grades: Second Lieutenant (O-1), First Lieutenant (O-2), Captain (O-3)
Field Grade Officers (O-5 through O-6): To achieve O-5 takes approximately 16 to 22 years time-in-service. They command between 300 and 1,000 Marines.
Pay Grades: Major (O-4), Lieutenant Colonel (O-5), Colonel (O-6)
Generals: Generals in the Marine Corps start off by presiding over 10,000 to 15,000 Marines, and are in charge of tactical planning and coordination of operations. Three-star generals (O-9) can only extend their status through an act of Congress. There may only be 60 total generals in the Marine Corps, and 3 of those can be four-star generals.
Pay Grades: Brigadier General (O-7), Major General (O-8), Lieutenant General (O-9), General (O-10).
Note: O-3 through O-10 Officer Ranks are not achievable ranks within the Platoon, they are listed as reference only.
(2ndLt.) Second Lieutenant, O-1 (1stLt.) First Lieutenant, O-2 (Capt.) Captain, O-3 (Maj.) Major, O-4 (LtCol.) Lieutenant Colonel, O-5 (Col.) Colonel, O-6 (BGen.) Brigadier General, O-7 (MajGen.) Major General, O-8 (LtGen.) Lieutenant General, O-9 (Gen.) General, O-10