Officers out rank all enlisted personnel. So, it would be an officer. The third highest would be a Lieutenant General (O-9). That's assuming there's an 0-11, General of the Army that is active, which it isn't all the time. In that case it would be one rung lower, Brigadier General (O-8).
Assuming you're talking about the US Army (which is where the question is categorized), the rank would be General (four stars), and the position... well, depends on how you look at it.. the Chief of Staff of the Army is the ranking Army officer, although the Chairman of the Joint Chiefs of Staffs (who could come from any of the service branches) would be the ranking officer of all military forces.
Field Marshal is the highest military rank in Pakistan Army.
Sergeant Major of the Army is the highest rank NCO.
Imperator
General
General
Sergeant Major of the Army
In the US Army, General.
The highest Non-Commissioned Officer rank in the US Army is Sergeant Major of the Army. The current SMOA is Kenneth O. Preston.
General of the Army- 5 stars, arranged in a circle.
The highest rank is Field Marshal, currently held by Queen Elizabeth's husband, the Duke of Edinburgh. It is a purely ceremonial role. Following that is the rank of General which is held by the Chief of the Defence Force (a role that rotates through the heads of the three services) and then Lieutenant General. Therefore if the current Chief of the Defence Force is from the Army then the highest Army rank is General, otherwise it is Lieutenant General.
George Washington's highest military rank was commander in chief of the Continental Army.
Victoria Cross (VC)