On 23 December 1956, the Territorial Assembly of Cameroon () was replaced by the Legislative Assembly of Cameroon () and parliamentary elections were scheduled. Candidates were authorised to present themselves in their own name. Mbida and his team (Cococam et affiliated memberships) ) stood for election. At ALCAM, they created the Parliamentary Group of Cameroonian Democrats composed of 21 members with Mbida as leader. Mbida set up the internal autonomy of the UN Trust Territory of the Cameroons under French administration. On 16 April 1957, the latter became an autonomous State. On 12 May 1957, by 56 votes against 10 votes and 4 abstentions, he was appointed first President of the Council of Ministers, first head of government and the facto Head of State of French speaking Cameroon. This designation was very symbolic because he was the second African-born Prime Minister in the Sub-Saharan Africa and the first Head of State of Cameroon.