William Pick was born in 1876 into a poor working-class family in Guben. Joined the German Social Democratic Party in 1895. Due to disappointment with the cooperation between the party leadership and conservative forces during World War I, he became an early member of the Spartak League and participated in the establishment of the German Communist Party. In 1933, he was forced to flee from Germany under Hitler's rule. In April 1946, the Social Democratic Party of Germany merged with the Communist Party of Germany to form the Socialist Unity Party of Germany, and was elected as one of the two chairpersons of the Socialist Unity Party along with Otto Grotiver. When the German Democratic Republic was established in 1949, he became the only president of East Germany.