The SEDEF is a civilian which is appointed by the King with the advice of the Defence Minister.

In spite of being the second authority of the Ministry, it is behind the Chief of the Defence Staff as far as military control is concerned.

The duties of the SEDEF are related to management and control of the economic resources, the armament policy and the defence infraestructures.

[2] The current functions are regulated by a Royal Decree of 2017, and are the following:[3] The Secretary of State for Defense is the highest body of the Department responsible for the direction, promotion and management of weapons and material policies, and for the research, development and industrial, economic, infrastructure, environmental and systems, technologies and security of information innovation in the field of Defence.

Apart from these, SEDEF can carry out all those functions delegated to it by the Minister of Defense.