Senior enlisted advisor

A Senior Enlisted Advisor (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. Formal, 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.

Examples

 * Senior Enlisted Advisor to the Chairman
 * Sergeant Major of the Army
 * Sergeant Major of the Marine Corps
 * Master Chief Petty Officer of the Navy
 * Chief Master Sergeant of the Air Force
 * Master Chief Petty Officer of the Coast Guard
 * Senior Enlisted Advisor for the National Guard Bureau

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.

Australia
In Australia the equivalent positions within the Royal Australian Navy (RAN), Australian Army and Royal Australian Air Force (RAAF) are Warrant Officer of the Navy (WO-N), Regimental Sergeant Major-Army (RSM-A) and Warrant Officer of the Air Force (WOFF-AF) respectively.

Canada
The Senior Enlisted advisor of the Canadian Forces is the Canadian Forces Chief Warrant Officer. The Army, Navy and Air Force each have their own Warrant Officer acting as Senior Enlisted advisor

NATO
NATO also has a number of Senior Enlisted Advisors taken from NATO members for various posts, including Senior Enlisted Advisor - NATO Allied Command Transformation

South Africa
South Africa has a Warrant officer of the Defence Force, as well as Sergeant Majors of the Army, Air Force and Medical Services. The Navy equivalent is the Master at Arms of the Navy

United Kingdom
The Royal Navy has the Warrant Officer of the Naval Service, the British Army has the Army Sergeant Major, the Royal Air Force has the Chief of the Air Staff's Warrant Officer and the Royal Marines the Corps Regimental Sergeant Major.