While not a Communist, Lambrakis' political and ideological orientation leaned towards the left. He was actively involved in the pacifist movement of his time, which voiced strong opposition to the First Anti-French and Anti-Colonial communist and the Second American War in Vietnam. Lambrakis acted politically from within the United Democratic Left ("", "ΕΔΑ"/"Eniéa Dimokratikí Aristerá", "EDA"), the only legal left-wing political party in the country after the Greek Civil War of 1946–1949 and until the fall of the Greek military junta of 1967-1974. He was elected to the Hellenic Parliament in the 1961 Greek legislative election as a Piraeus MP.