Senior enlisted adviser

A Senior Enlisted Adviser (SEA) in the United States Armed Forces is the most senior enlisted service member in a unit, and acts as an advisor to the commanding officer. Formally, E-9 billets for the senior enlisted advisor are established at Service unit (e.g., battalion, wing, or higher), command, major command, force, or fleet levels to the SEAs/CSELs of DoD Agencies and the Senior Enlisted Advisor to the Chairman of the Joint Chiefs of Staff. SEAs are also known as Command Senior Enlisted Leaders (CSEL). Always a non-commissioned officer, the SEA is the main link between the commanding officer and the enlisted service members under his or her charge.

In the United States Army, the SEA for a battalion or larger-sized unit is usually a Command Sergeant Major. For Marine battalions and larger, Sergeant Major typically takes the role. Navy ships and other commands will usually have a Command, Fleet, or Force Master Chief Petty Officer (known as the Chief of the Boat on a submarine), while an Air Force Command Chief Master Sergeant serves at Wing, Numbered Air Force, Field Operating Agency (FOA), Major Command or at "Joint," DoD Agency levels.

In the United States Army and the United States Marine Corps, the senior enlisted advisor at the company or battery level (or other unit at similar echelon) is a First Sergeant. In the Air Force, the senior enlisted member of units smaller than those listed above for Command Chief Master Sergeant is also a First Sergeant. It is a temporary, special duty assignment. However, in the Air Force a First Sergeant can be an E7, E8 or E9, depending on size and mission of the unit.

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