The foundation of the party followed the coming into force of the Memel Convention and the Memel Statute on August 25, 1925, after which the labour movement in the Memel Territory detached itself organizationally from the German labour movement. The party was founded on the basis of the erstwhile organization of the Social Democratic Party of Germany in the area. Parallel to the foundation the Social Democratic Party of the Memel Territory, an independent Memel trade union movement was created. The party was divided into four district organizations : Memel-Stadt, Memel-Land, Heydekrug and Pogegen. The social base of the party differed significantly between the four districts. In Memel city the party had a strong support amongst industrial and port workers. In the Memel-Land district there was representation of industrial, agricultural and commercial workers. In Pogegen, a rural area, party members were predominately agricultural labourers.
First election
The party contested the first elections to the Parliament of the Klaipėda Region, held in October 19, 1925. The party formed a Unity Front together with the two other main German parties, the Memel Agricultural Party and the Memel People's Party. Together these three parties won 27 out of 29 seats in the regional parliament. The main opponents of the social democrats were the Greater Lithuanian nationalists. The Social Democratic Party obtained 10,010 votes and 5 seats. The elected parliamentarians of the party were August Kislat, Adolf Plennis, Michel Bertschus, Ernst Rausch and Martin Seewaldt.
The party contested the 1926 Lithuanian parliamentary election. The party won 13.27% of the votes in Memel Territory/Klaipėda Region but failed to win any seat. The vote for the list of the party dipped to 5,712 votes in the August 30, 1927 election to the Parliament of the Klaipėda Region. Three parliamentarians were re-elected; Kislat, Bertschus and Seewaldt. The declaration of Martial Law in 1926 made party activities more complex.
1930s
In the 1930s the party revived the publication of Memelländische Volkszeitung, a publication founded in 1924. The party obtained 6,780 votes in the October 10, 1930 Parliament of the Klaipėda Region election. The party gained four seats in the parliament; held by Michel Bertschus, August Jöres, Georg Pannars and Eugen Urban. As the political situation in the area became increasingly difficult, the party faced competition from National Socialist tendencies. In the fourth Parliament of the Klaipėda Region election, the last contested by the party, held on May 4, 1932 the party obtained 5,104 votes. Pannars and Jöres were re-elected. Jöres renounced his seat on May 26, 1932 and was replaced by Kislat. The party dissolved into the Memel Unity List in 1935.
