Ella Reeve Bloor was born on Staten Island, on 8th July, 1862. Bloor grew up in New Jersey and after marrying Lucian Ware when she was nineteen, she was a mother of four by 1892. One of her sons was Harold Ware.
Bloor became involved in several reform movements including the Women's Christian Temperance Union (WCTU) and women's suffrage and wrote two books, Three Little Lovers of Nature (1895) and Talks About Authors and Their Work (1899).
In 1897 she joined with Eugene Debs and Victor Berger to form the Social Democratic Party (SDP). The following year she moved to the more radical Socialist Labor Party that was led by Daniel De Leon. However, in 1902 she became a member of the Socialist Party of America (SPA). Other members included Eugene Debs, Victor Berger, Emil Seidel,Philip Randolph, Chandler Owen, William Z. Foster, Abraham Cahan, Sidney Hillman, Morris Hillquit, Bill Haywood, Margaret Sanger, Florence Kelley, Inez Milholland, Floyd Dell, William Du Bois, Hubert Harrison, Upton Sinclair, Victor Berger, Robert Hunter, George Herron, Kate Richards O'Hare, Claude McKay, Sinclair Lewis, Daniel Hoan, Frank Zeidler, Max Eastman, Bayard Rustin, James Larkin, William Walling and Jack London.
Bloor worked as a trade union organizer and helped during industrial disputes in Pennsylvania, Michigan, Colorado, Ohio and New York. In 1905 she helped a fellow member of the Socialist Party of America, the author, Upton Sinclair, to gather information on the Chicago stockyards. This material eventually appeared in Sinclair's best-selling book, The Jungle. A leading figure in the party, she ran several times unsuccessfully for political office, including secretary of state for Connecticut and lieutenant governor of New York.
Elizabeth Gurley Flynn first met Bloor in 1910 and later recalled that she "moved as if she were flying rather than walking". She herself said in her autobiography, We Are Many, that it was a "privilege and joy to carry the torch of socialism".
The right-wing leadership of the Socialist Party of America opposed the Russian Revolution. On 24th May 1919 the leadership expelled 20,000 members who supported the Soviet government. The process continued and by the beginning of July two-thirds of the party had been suspended or expelled. Some of these people, including Ella Reeve Bloor, Rose Pastor Stokes, Earl Browder, John Reed, James Cannon, Elizabeth Gurley Flynn, Claude McKay, Michael Gold and Robert Minor, decided to form the American Communist Party. By August 1919 it had 60,000 members.
In 1921 and 1922 attended the Second International conventions in Moscow and was a member of the party's central committee (1932-48). By the 1930s she became known as "Mother" Bloor. Although now in her seventies she continued to play an important role in political life. According to Mari Jo Buhle: "She continued to maintain an active schedule, taking part in hunger marches, demonstrating on behalf of unemployed workers, and helping to build the Farmers National Committee for Action."
In 1937 Bloor returned to the Soviet Union to celebrate the twentieth anniversary of the Bolshevik Revolution. Upon her return she published Women in the Soviet Union (1938), a pamphlet that praised the Soviet system of child care.
After the German Army invaded the Soviet Union in June 1941, Bloor became an advocate of American participation in the Second World War. Later she argued for an early invasion of Europe to create a Second Front.