Junior Enlisted

• Junior enlisted personnel are the lowest ranking members of their respective service. These service members generally have the least experience and little to no command authority. They fall between the classification of E-1 through E-4. In the Air Force, for example, this would correspond to someone holding the rank of Airman Basic, Airman, Airman First Class and Senior Airman. Personnel holding these ranks are typically recruits or those who have recently completed boot camp but have not yet completed the necessary education in their chosen job speciality.
  
  

Senior Enlisted

• Senior enlisted personnel have greater experience than both junior enlisted and many junior officers. They have authority over junior enlisted personnel, serve as job supervisors and act as technical instructors or specialists. Referred to as non-commissioned officers, these ranks fall between the classifications of E-5 through E-7. In the Army these would include the ranks of Sergeant, Staff Sergeant, Sergeant First Class. The ranks of E-8 and E-9, Sergeant Major and Sergeant Major of the Army, are top-level enlisted ranks whose personnel act as senior advisors and spokesmen for enlisted matters.
  
  

Warrant Officers

• Warrant Officers are military members who hold a warrant issued by their respective service secretary, rather than a Presidential Commission and are considered specialists in a given field. For example, an Army helicopter pilot is typically a warrant officer assignment. While they are not considered commissioned officers, they are entitled to wear officer uniforms and receive salutes from their subordinates. These ranks are classified as W-1 through W-5 and are titled as Chief Warrant Officer, followed by whichever level the members hold. The Air Force is the only service that does not have warrant officers among its ranks.
  
  

Company Grade Officers

• These officers are the most junior of all commissioned officers. They hold authority over all enlisted and warrant officer personnel and are considered their superiors. Their rank classifications are O-1 through O-3. In the Coast Guard and the Navy, this would include the ranks of Ensign, Lieutenant Junior Grade and Lieutenant, and denotes someone who would oversee an entire division or a department such as communications or navigation. The rank titles in the Army, Marines and Air Force would be Second Lieutenant, First Lieutenant and Captain.
  
  

Field Grade Officers

• Field grade officers are mid-level officers who have greater responsibility and authority based upon their service and experience. Classified as O-4 through O-6, these ranks correspond to Major, Lieutenant Colonel and Colonel in the Marines, Army and Air Force. The ranks in the Navy and the Coast Guard would be Lieutenant Commander, Commander and Captain. Officers in these ranks often serve as executive officers or commanding officers over an entire post or ship.
  
  

General Grade Officers

• Rank classifications O-7 through O-10 represent the most senior officers in the military. These are Brigadier General, Major General, Lieutenant General and General, respectively, in the Army, Marines and Air Force. The Navy and Coast Guard refer to these officers as Rear Admiral Lower Half, Rear Admiral Upper Half, Vice Admiral and Admiral, respectively. Furthermore they are collectively known as either General Officers, or in the case of the Navy and the Coast Guard, Flag Officers. These officers command entire army groups, naval fleets and serve as top military advisors to government officials.
  
  

Wartime

• Five Star General or Admiral insignia. Photo courtesy of Wikipedia.
  
  The Army, Navy and Air Force each retain a special rank that is used in wartime only. These ranks were first introduced in World War II as a means to equate a senior American general or admiral to a Field Marshal. An army or air force five star general, so known because of their distinctive insignia, is referred to as General of the Army or General of the Air Force. The Navy counterpart is called a Fleet Admiral.