In the 1910 elections socialist and agrarian Members of Parliament were elected for the first time, thus marking the entrance of political trends directly related to class into the Greek parliamentary arena.

The Socialist members represented vague pre-socialist trends but their presence was intermittent: an organized Socialist presence on an electoral basis only emerged from the elections of 1920 onwards with SEKE (the Socialist Labour Party of Greece). Those that supported the interests of peasants in Thessaly foreshadowed in a way an agrarian party, even though some reservations were expressed concerning this.

Until the beginning of the twentieth century Socialist ideas had very little impact in Greece, a country with economic and social features different from those of the industrial societies of western Europe and North America. There are many reasons why the spread of socialist ideas was hindered: the embryonic state of the labouring classes, emigration as an outlet for the poorer elements of society, the prevalence of the Great Idea, the patron-client relationships of Greek political parties, the disruption of class structures - all of these played their part.

During this period Socialist ideas concerning the class struggle as a policy guideline spread more and more, as did the independence of the labour movement from middle class political parties. Apart from the League of the Working Classes of Greece (or Greek Socialist Party) founded by Platon Drakoulis, the Socialist Centre of Athens and its youth department, the Socialist Club of Greek Youth were founded by Nikolaos Yannios in 1911.

After 1915, the plight of the labour class, the defective implementation of Venizelist labour legislation, the additional ill luck due to the conditions of war and the wide dissemination of socialist ideas tended to instil a socialist consciousness and radicalize the Greek labouring classes.
In 1918 the Socialist Labour Party of Greece (SEKE) was founded in Athens, following a decisive boost of Venizelos's government (as was the case with the foundation of the General Confederation of the Workers of Greece [GSEE] in that same year), which sought to draw a favourable picture of Greece to international labour and Socialist organizations in order to gain supporters among them in favour of Greece's national issues.
SEKE acceded to the 3rd International in 1920 and was later renamed into Communist Party of Greece (KKE).

SEKE was the only purely labour party in Greece during this period, as was the case with KKE in the inter-war period. It did not win the support of the majority of the labouring classes, who had initially supported the Recovery movement and its political expression, the Liberal party, while later it turned to the anti-Venizelist bloc preaching peace (in the elections of 1920). In this election many workers voted for SEKE.