Joseph Zack Kornfeder

Joseph Zack Kornfeder (1898–1963), also known as Joseph Zack and to his friends as "Joe," was an Austro-Hungarian-born American who was a founding member and top leader of the Communist Party of America in 1919. Zack was a Representative of the Communist International to South America from 1930 to 1931, before quitting the Communist Party in 1934.

After his wife, who he had to leave in the Soviet Union, was arrested by the secret police during the Great Terror of 1937-38, Zack moved to a position of vehement anti-Communism, testifying before the Dies Committee of the US Congress as a friendly witness in 1939 and the Canwell Committee of the Washington State Legislature in 1948.

Joseph Zack Kornfeder, perhaps better known by his mother's maiden name as "Joseph Zack," was born in Trenčín, Austria-Hungary (now Slovakia) on March 20, 1898. Zack's parents were ethnic Austrians and they raised their son as a Roman Catholic.

As a young man, Joseph went to Spain, where he joined the Spanish Socialist Workers' Party at age 16. This early knowledge of Spanish would later be put to use by the Comintern when it stationed him to Central America.

The family emigrated to the United States in 1915, landing in New York City, where they made a home. Zack took a job as a garment worker and joined the Socialist Party of America within a year after his arrival.

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