In 1927 Messali Hadj was elected leader of an Algerian workers' association based in Paris. He attended the Anti-Imperialism Congress in Belgium that year, which created the League against Imperialism, and met with Vietnam's Ho Chi Minh. Back in France and in his native Algeria, then a French colony, Messali helped build an underground movement and work towards Algerian independence. In the 1920s he started Étoile Nord-Africaine (North African Star), one of the first modern Algerian nationalist organizations, and in 1937 he founded the Algerian People's Party (PPA). Both groups were suppressed by France, and in November 1937, Messali was put on trial for agitation, and imprisoned for several years.
In May 1945, nationalist riots and clashes between French troops and native Algerians during World War II victory celebrations led to reprisals; tens of thousands of Algerians were killed. Many realized then that the independence movement would not succeed by peaceful means.
In 1946 Messali founded the Mouvement pour le Triomphe des Libertés Démocratiques (MTLD). Messali lived under house arrest in Brittany, France, and could not travel to Algeria. His group was perceived as moderate and accommodating, but his revolutionary ideals alienated parts of Algeria's conservative Muslim society. Messali's brand of Algerian nationalism gained its most important following among Algerian workers in France, while the FLN and other grass-roots groups took hold in Algeria.
After the outbreak of the Algerian War of Independence in 1954 which was started against his wishes, Messali created the Mouvement National Algérien, or MNA (French Algerian National Movement). Messali's followers clashed with the FLN; his was the only socialist faction not absorbed into the Front's fight for independence. The FLN's armed wing, the Armé de Libération Nationale (ALN) wiped out the MNA's guerrilla apparatus in Algeria early on in the war; the infighting then continued in France, during the so-called "café wars" over control of the expatriate community. In 1958 Messali supports the proposals of President de Gaulle and France probably attempted to capitalize on the internal rivalries of the nationalist movement. During negotiation talks in 1961 the FLN did not accept the participation of the MNA and led to new outbursts of fighting.
In 1962, as Algeria gained independence from the government of Charles de Gaulle, Messali tried to transform his group into a legitimate political party, but it was not successful, and the FLN seized control over Algeria as a one-party state.
Messali Hadj remained in exile near Paris, with little influence over Algerian poltiics. He died in 1974.