Force Ouvrière was founded in 1948 by former members of the General Confederation of Labor (CGT) who denounced the dominance of the French Communist Party over that federation. Various sources, including former CIA officials, have suggested that this split was instigated by the Central Intelligence Agency (CIA) and that FO had received funds from the CIA through the American Federation of Labor (AFL)'s Irving Brown.
After World War II, members of the French Communist Party attained considerable influence within the CGT, controlling 21 of its 30 federations. Senior figures such as Robert Bothereau and the former secretary general, Léon Jouhaux, opposed this development. These opponents denounced Communist influence as a threat to the independent position of trade unions, a principle enshrined in the 1906 Charte d'Amiens. They founded a paper, Force ouvrière.
In 1947, a general strike, fought against the backdrop of the developing Cold War, divided the CGT. The Communist ministers were excluded from the government led by Paul Ramadier, a Socialist. In this context, the internal CGT opposition created a new trade-union confederation, called FO. The majority of its founders were from the socialist ranks.
In February 1958 the African branches of FO became an independent organization, Confédération Africaine des Syndicats Libres-FO.