Morris Hillquit (1869-1933), was born in Riga, Latvia, and immigrated to the United States with his family in 1886, settling in New York City. He joined the Socialist Labor party in 1887 or 1888 and was part of a faction that broke with Daniel DeLeon 's leadership in 1899. Two years later he participated in the formation of the Socialist Party of America. Hillquit emerged as a leading figure in the Socialist party and served as a member of its national executive committee (1907-12, 1916-19, 1922-33) and as party chairman (1929-33).

In 1888 Hillquit helped found the United Hebrew Trades and was its first corresponding secretary. He graduated from the law school of the University of the City of New York in 1893 and subsequently developed a successful law practice that included serving for many years as counsel to the International Ladies' Garment Workers'
Union (1914-33). He was also a director, trustee, and lecturer at the Rand School and the author of a number of works on socialism. Hillquit twice ran unsuccessfully on the Socialist party ticket for mayor of New York City (1917, 1932) and was five times a candidate for the U.S. House of Representatives (1906, 1908, 1916, 1918, 1920).