Born Zorach Gorfinkel in 1889, in Jurbarkas (Russian: Eurburg) in Lithuania as the eighth of ten children, Zorach (then his given name) emigrated with his family to the United States in 1894. They settled in Cleveland, Ohio under the name "Finkelstein". In school, his first name was changed to "William" by a teacher.
He married Marguerite Thompson (1887-1968) in 1911. The couple adopted his original given name, Zorach, as a common surname. In 1964 Zorach received a D.F.A. from Bates College. He taught at the Art Students League of New York between 1929 and 1960. His daughter, Dahlov Ipcar, is an artist also. She currently resides in Maine.
He died in Bath, Maine, on 15 November 1966.