The construction of the Council Chamber started late in 1936 to accommodate the members of the League of Nations. The setting and the furnishings of the square-shaped room were assigned to the Parisian decorator René Prou. Contrary to the other rooms of the Palais, the Council Chamber did not have a podium but a large table for 21 persons situated in a semicircle in front of the five windows overlooking the park. Between March 1935 and May 1936, the walls and the ceiling of the Council Chamber were decorated with gold and sepia murals, painted by the Catalan artist José Maria Sert, depicting the progress of humankind through health, technology, freedom and peace, and offered by the Government of Spain to the League of Nations. Two monumental bronze doors with inscriptions in Latin, masterpieces of Raymond Subes, open on the two sides of the chamber. On 2 October 1936, the room was inaugurated.
From 1951 to 1968, the Council Chamber underwent a series of transformations due to the needs of an expanded United Nations, in particular that of the Economic and Social Council, as well as of the Security Council. The architect Jacques Carlu was entrusted to create a polyvalent conference room while keeping its beauty and majesty. Climatized interpreters' booths for simultaneous interpretation were created, the necessary technical equipment was installed and new furnishings were ordered. The podium was horseshoe-shaped in order to accommodate 23 persons at the table. It was moved closer to the centre of the room, with the President sitting in the middle and two seats behind each chair.
In 1968, within a programme of improvement and major maintenance work (A/C.5/1009 and A/C.5/1040), a fund was allocated for the renovation of the room. An improved system of ventilation and more sophisticated technical equipment were installed, as well as new furniture.
On 2 October 1986, to celebrate the 50th anniversary of the room, the Government of Spain offered a commemorative plaque, located inside the room.
The Council Chamber hosted the negotiations to end the 1991 Gulf War, several special sessions of the Security Council and it continues to accomodate the meetings of the Conference on Disarmament.