The United Nations takes very seriously the shared responsibility and shared aims of the organisation's endeavour. Therefore the person in charge of the UN is a Secretay General chosen in rotation. At the moment this leader is from Portugal. Before this it was Ban-Ki-Moon of Korea.
The United Nations (UN) army is controlled by the UN’s Office of Military Affairs. The peacekeeping forces on the ground in various locations throughout the world are led in the field typically by a civilian Head of Mission (usually a Special Representative of the Secretary-General). The “UN has no standing army or police force of its own.
Military and police personnel, from UN member states… are members of their own national service first and are seconded to work with the UN. They wear their countries' uniform and are identified as UN Peacekeepers by a UN blue helmet or beret.”