Combined Chiefs of Staff The Combined Chiefs of Staff ( CCS ) was the supreme military staff for the western Allies during World War II . It emerged from the meetings of the Arcadia Conference in December 1941 . The CCS was constituted from the British Chiefs of Staff Committee and the American Joint Chiefs of Staff that was created , in part to present a common front to the British Chiefs of Staff , in early 1942 holding its first formal meeting on 9 February to coordinate U . S . military operations between War and Navy Departments . After its first meeting 23 January 1942 in the Public Health Building at Nineteenth Street and Constitution Avenue in Washington , the CCS charter was approved by President Roosevelt 21 April 1942 . The American members of the CCS were General George C . Marshall , the United States Army chief of staff , the Chief of Naval Operations , Admiral Harold R . Stark ( replaced early in 1942 by Admiral Ernest J . King ) ; and the Chief ( later Commanding General ) of the Army Air Forces , Lt . Gen . Henry H . Arnold . In July 1942 a fourth member was added , the President ' s personal Chief of Staff , Admiral William D . Leahy . On the British side the Chiefs of Staff only normally attended during the heads of states ' conferences . Instead the British Joint Staff Mission was permanently situated in Washington , D . C . to represent British interests . The British members were a representative of the Prime Minister , in his capacity as Minister of Defence , and the Chiefs of Staff Committee , which consisted of the First Sea Lord , the Chief of the Imperial General Staff , and the Chief of the Air Staff , or the Washington representative of each . The representative of the Prime Minister was Field Marshal Sir John Dill and after his death Field Marshal Sir Henry Maitland Wilson . The Washington representatives of the Chiefs of Staff Committee , who normally met with the United States members in place of their principals , were the senior officers from their respective services on the British Joint Staff Mission in Washington . In the course of the war , the First Sea Lord was represented by Admiral Sir Charles Little , Admiral Sir Andrew Cunningham , Admiral Sir Percy Noble , and Admiral Sir James Somerville ; the Chief of the Imperial General Staff was represented by Lt . Gen . Sir Coville Wemyss and Lt . Gen . G . N . Macready ; and the Chief of the Air Staff was represented by Air Marshal D . C . S . Evill , Air Marshal Sir William L . Welsh , and Air Marshal Douglas Colyer . The Combined Chiefs of Staff organization included the Combined Secretariat and a number of committees . In the Northern hemisphere spring of 1942 , Britain and the United States agreed on a worldwide division of strategic responsibility . On 24 March 1942 , the U . S . Joint Chiefs of Staff were designated as primarily responsible for the war in the Pacific , and the British Chiefs for the Middle East - Indian Ocean region , while the European - Mediterranean - Atlantic area would be a combined responsibility of both staffs . China was designated a separate theater commanded by its chief of state , Chiang Kai - shek , though within the United States ' sphere of responsibility . Six days later the Joint Chiefs of Staff divided the Pacific theater into three areas : the Pacific Ocean Areas ( POA ) , the South West Pacific Area ( SWPA ) , and the Southeast Pacific Area . The Pacific Ocean Area command formally became operational on 8 May . The CCS usually held its meetings in Washington , D . C . . The full CCS usually met only during the great wartime conferences on grand strategy , such as at Casablanca ( see List of World War II conferences ) . The meetings of heads of government at those conferences were designed to reach formal agreement on issues thoroughly staffed by the CCS . At the Casablanca Conference in January 1943 , General Frank Maxwell Andrews was appointed commander of all United States forces in the European Theater of Operations . Although it was responsible to both the British and American governments , the CCS controlled forces from many different countries in all theaters , including the Pacific , India and North Africa . Representatives of allied nations were not members of the CCS but accepted procedure included consultation with " Military Representatives of Associated Powers " on strategic issues . Much cooperation continued between the British and American militaries after the war including the Combined Chiefs of Staff structure , and it was used again during the Berlin Blockade of 1948 even as negotiations began that resulted in the North Atlantic Treaty Organization .