In the army who commands who?

Ok, all these answers are fine and correct to an extent, but they are missing some context (excluding the guy that just listed ranks).

An Officer (O-1 through O-10) outranks an Enlisted (E-1 through E-9). There are two basic separations of Officers, field grade (which is O-4 and up) and non-field grade (which is O-1 through O-3). There are also two basic separations of Enlisted; NCO (Non-Commissioned Officers E-5 and up with sometimes E-4) and lower Enlisted (E-1 through E-3/E-4). E-4 may be sometimes called a Junior NCO.

Now, there are two types of orders in general; a direct order which is only given by an Officer, and a legal order which can be given by NCOs. As a Staff Sergeant, I can issue orders and they are considered to be legal orders. If you don't follow my orders, you can still get in trouble for failure to follow orders. I cannot issue direct orders. This is the same kind of thing with "punishment". Only an Officer can issue punishment (which would be through an Article 15 or other UCMJ actions), but what an NCO can issue is corrective training.

Command Structure:

Although technically an O-1 can issue an order to an E-9, it is not going to happen. I'm going to use Army terminology here. An O-1 or O-2 (Platoon Leader/Lieutenant) will have a Platoon that he/she is in charge of. This is co-run with an E-7 (Platoon Sergeant/SFC). The Lieutenant will give his guidance or orders to the Platoon Sergeant. The Platoon Sergeant will then give his orders to his Squad Leaders or Section Sergeants (E-6/SSG) who then gives orders to the Team Leaders (E-5/E-4). The Lieutenant doesn't typically give orders to the Team Leaders as that is considered micro-managing. This same goes at the Company level. It is run by an O-3 (Company Commander/Captain) and his/her counterpart is an E-8 (First Sergeant/1SG). The Captain will give his guidance to the 1SG as well as the Lieutenants. The 1SG will give his guidance to the Platoon Sergeants. Do you see the pattern here? For a Battalion, it has an O-5 (Lt. Colonel) and an E-9 (Command Sergeant Major). Now, as a SSG/E-6 I can receive orders from anybody that outranks me, but typically I will receive my orders from my Platoon Sergeant and maybe sometimes from my Lieutenant. I don't get orders directly from my Captain and definitely not from my Colonel. That is not how the command structure works.

Uh...yeah.

An O-3 is a Captain and is typically a Company Commander and commands anywhere from 100-170 people depending on the type of unit. Which will include about 20 or more E-5s.

An O-1 is typically a Platoon Leader in charge of 35-50 people which will include three or more E-6s.

O officer ranks are always higher than E ranks.

So an O-1 can order any E-rank in his chain of command to no matter what.

Oh, your question isn't a LITTLE stupid...

Of course. O to E is acceptable. Technique goes a long way when you're talking O-1 to E-9 orders, but as long as it is legal, it's an order.

Marine Corps

E-1 Private (PVT)

E-2 Private First Class (PFC)

E-3 Lance Corporal (LCpl)

E-4 Corporal (Cpl)

E-5 Sergeant (Sgt)

E-6 Staff Sergeant (SSgt)

E-7 Gunnery Sergeant (GySgt)

E-8 First Sergeant (1SG)

E-8 Master Sergeant (Msgt)

E-9 Sergeant Major (SgtMaj)

E-9 Master Gunnery Sergeant (MGySgt)

E-9 Sergeant Major of the Marine Corps (SgtMajMC)

W-1 Warrant Officer 1 (WO)

W-2 Chief Warrant Officer 2 (CWO2)

W-3 Chief Warrant Officer 3 (CWO3)

W-4 Chief Warrant Officer 4 (CWO4)

W-5 Chief Warrant Officer 5 (CWO5)

O-1 2nd Lieutenant (2nd Lt)

O-2 1st Lieutenant (1st Lt)

O-3 Captain (Capt.)

O-4 Major (Maj.)

O-5 Lieutenant Colonel (Lt. Col.)

O-6 Colonel (Col.)

O-7 Brigadier General (Brig. Gen.)

O-8 Major General (Maj. Gen.)

O-9 Lieutenant General (Lt. Gen.)

O-10 General (Gen.)

O-10 Commandant of the Marine Corps (CMC)

Army

E-1 Private (PVT)

E-2 Private (PVT)

E-3 Private First Class (PFC)

E-4 Specialist (SPC)

E-4 Corporal (CPL)

E-5 Sergeant (SGT)

E-6 Staff Sergeant (SSG)

E-7 Sergeant First Class (SFC)

E-8 First Sergeant (1SG)

E-8 Master Sergeant (MSG)

E-9 Sergeant Major (SGM)

E-9 Command Sergeant Major (CSM)

E-9 Sergeant Major of the Army (SMA)

W-1 Warrant Officer 1 (WO1)

W-2 Warrant Officer 2 (CW2)

W-3 Warrant Officer 3 (CW3)

W-4 Warrant Officer 4 (CW4)

W-5 Master Warrant Officer 5 (CW5)

O-1 2nd Lieutenant (2nd Lt)

O-2 1st Lieutenant (1st Lt)

O-3 Captain (Capt.)

O-4 Major (Maj.)

O-5 Lieutenant Colonel (Lt. Col.)

O-6 Colonel (Col.)

O-7 Brigadier General (Brig. Gen.)

O-8 Major General (Maj. Gen.)

O-9 Lieutenant General (Lt. Gen.)

O-10 General (Gen.)

O-10 Army Chief of Staff (ACS)

General of the Army (Wartime only)

Navy/Coast Guard

E-1 Seaman Recruit (SR)

E-2 Seaman Apprentice (SA)

E-3 Seaman (SN)

E-4 Petty Officer Third Class (PO3)

E-5 Petty Officer Second Class (PO2)

E-6 Petty Officer First Class (PO1)

E-7 Chief Petty Officer (CPO)

E-8 Senior Chief Petty Officer (SCPO)

E-9 Master Chief Petty Officer (MCPO)

E-9 Master Chief Petty Officer of the Navy (MCPON)

W-1 Warrant Officer 1 (WO)

W-2 Warrant Officer 2 (CWO2)

W-3 Warrant Officer 3 (CWO3)

W-4 Warrant Officer 4 (CWO4)

W-5 Master Warrant Officer (CWO5)

O-1 Ensign (ENS)

O-2 Lieutenant, Junior Grade (LTJG)

O-3 Lieutenant (LT)

O-4 Lieutenant Commander (LCDR)

O-5 Commander (CDR)

O-6 Captain (CAPT)

O-7 Rear Admiral (Lower Half) RADM (LH)

O-8 Rear Admiral (Upper Half) RADM (UH)

O-9 Vice Admiral (VADM)

O-10 Chief of Naval Operations /Commandant of the Coast Guard (ADM)

O-10 Admiral (ADM)

Fleet Admiral (Wartime only)

Air Force

E-1 Airman Basic (AB)

E-2 Airman (Amn)

E-3 Airman First Class (A1C)

E-4 Senior Airman (SrA)

E-5 Staff Sergeant (SSgt)

E-6 Technical Sergeant (TSgt)

E-7 First Sergeant (1SG)

E-7 Master Sergeant (MSgt)

E-8 First Sergeant (1SG)

E-8 Senior Master Sergeant (SMSgt)

E-9 First Sergeant (1SG)

E-9 Chief Master Sergeant (CMSgt)

E-9 Chief Master Sergeant of the Air Force (CMSAF)

O-1 2nd Lieutenant (2nd Lt)

O-2 1st Lieutenant (1st Lt)

O-3 Captain (Capt.)

O-4 Major (Maj.)

O-5 Lieutenant Colonel (Lt. Col.)

O-6 Colonel (Col.)

O-7 Brigadier General (Brig. Gen.)

O-8 Major General (Maj. Gen.)

O-9 Lieutenant General (Lt. Gen.)

O-10 General (Gen.)

O-10 Air Force Chief of Staff

General of the Air Force (Wartime only)