He was born Georges Auguste Alexandre Cogniot in to a middle class family and graduated from École normale supérieure.
Prior to the Second World War he was elected to the French National Assembly as part of the Popular Front.
He was the representative of the PCF in the Executive Committee of the Communist International and also succeeded Paul Vaillant-Couturier as editor of L'Humanité.
Cogniot was arrested by the German police in 1941 but managed to escape alongside other prisoners and became active in the French Resistance and was responsible for Communist Party press.
In 1966, he was appointed member of the control commission responsible for examining the problems of orientation and selection in the public service of education.