A major in the U.S. Army typically serves as a battalion executive officer (XO) or as the battalion operations officer (S3). A major can also serve as a primary staff officer for a regiment, brigade or task force in the areas concerning personnel, logistics and operations. A major will also be a staff officer / action officer on higher staffs and headquarters. In addition, majors command augmented companies in Combat Service and Service Support units. U.S. Army majors also command Special operations companies, such as U.S. Army Special Forces companies, Civil Affairs companies, Military Information Support Operations companies, as well as certain types of separate, numbered vice lettered, Military Intelligence companies.
The Armor Branch of the United States Army is an active combat arms branch.
It was created provisionally in 1940 as Armored Force under Chief of the Armored Force, Brigadier General Adna R. Chaffee, Jr. and took control of all tank units in infantry and cavalry units
In the U.S. Army, sergeant major (SGM) refers to both a military rank and a specific leadership position. It is the highest enlisted rank, just above first sergeant and master sergeant, with a pay grade of E-9, NATO rank OR-9.
The leadership variation—command sergeant major (CSM)—is the senior enlisted advisor to the commanding officer. The leadership position carries with it certain ceremonial functions such as caring for the unit's colors (flag). Additionally, CSMs serve as monitors of, and advocates for, the enlisted soldiers in the command. This position mostly exists in units of battalion size and larger.
Major is a military rank of commissioned officer status, with corresponding ranks existing in many military forces throughout the world.When used unhyphenated, in conjunction with no other indicators, major is one rank senior to that of an army captain, and one rank subordinate or below the rank of lieutenant colonel. It is considered the most junior of the field officer ranks.
Majors are typically assigned as specialised executive or operations officers for battalion-sized units of 300 to 1,200 soldiers. In some militaries, notably France and Ireland, the rank of major is referred to as commandant, while in others it is known as captain-major