The organisation was founded by former members of the Sierra Leonean branch of the National Congress of British West Africa around Herbert Bankole-Bright and Isaac Wallace-Johnson in 1950.
The National Council stood in opposition to the Stevenson Constitution of 1947, instead calling for a federal state, with the colony and the protectorate having separate assemblies.
In the 1951 elections, it initially appeared that the National Council had won more seats than the Sierra Leone People's Party (SLPP).
However, all the independent members from the protectorate later declared for the SLPP, placing the National Council a distant second.
When the SLPP failed to act on the constitution issue, the Council attempted to block all government business.