[1] The EUMS also reports to the European Union Military Committee (EUMC), representing member states' Chiefs of Defence, and performs "early warning", situation assessment and strategic planning.

The Common Foreign and Security Policy (CFSP) was introduced as a pillar of the EU by the Treaty of Maastricht in 1993, based on the earlier 1970 European Political Cooperation (EPC).

In December 1998 the Franco-British Saint-Malo declaration stated that the EU ‘must have the capacity for autonomous action, backed up by credible military forces, the means to decide to use them, and a readiness to do so, in order to respond to international crises’.

Upon the entry into force of the Treaty of Lisbon in 2009 the EUMS was transferred from the Council's General Secretariat to become a Directorate-General (DG) of the newly established European External Action Service (EEAS) - the EU's diplomatic service, a hybrid Council-Commission body resulting from a merger of the external relations departments of the Council and relevant international relations departments of the European Commission.

The implementation of this strategy in the field of CSDP has included the establishment of the Military Planning and Conduct Capability (MPCC), which gives the EUMS the role of commanding operations directly.

[6] The Communication and Information Systems Directorate (CIS) has the following tasks:[6] Other units at the EUMS include:[6] The EU command and control (C2) structure is directed by political bodies composed of member states' representatives, and generally requires unanimous decisions.