List of members of the Socialist Party of America

This is a selectively annotated list of the most prominent or important members of the Socialist Party of America (1901–1972).

Summary list
Key:
 * * Went on to join the Communist Party, Communist Labor Party of America or Workers Party of America
 * ISS A founder or key member of the Intercollegiate Socialist Society, 1905, later League for Industrial Democracy
 * IWW A founder of the Industrial Workers of the World, 1905.
 * SDL Left to found the Social Democratic League of America, 1917.
 * SDF Left to found the Social Democratic Federation, 1936.
 * IPN Left to found the Independent Party of Norwalk, 1951
 * SDUSA Continued into Social Democrats, USA, 1973
 * SPUSA Went on to join the Socialist Party USA, 1973
 * DSOC Went on to join the Democratic Socialist Organizing Committee, 1973, later Democratic Socialists of America


 * Martin Abern *
 * Devere Allen
 * Elmer Allison *
 * Harry Ault
 * J. Mahlon Barnes
 * David P. Berenberg
 * Victor L. Berger
 * Barney Berlyn
 * Allan L. Benson
 * Ella Reeve Bloor *
 * Nikolai Bukharin
 * Roy E. Burt
 * Frank Bohn IWW
 * Earl Browder*
 * Jack Carney *
 * James P. Cannon *
 * John C. Chase
 * Travers Clement
 * Joseph Coldwell
 * James Connolly
 * Eugene V. Debs IWW
 * Nicholas Dozenberg *
 * David Dubinsky
 * Max Eastman *
 * J. Louis Engdahl
 * Elizabeth Gurley Flynn *
 * William Z. Foster *
 * Louis Fraina *
 * Joseph Freeman *
 * Irving Freese IPN
 * Samuel Friedman SPUSA
 * Julius Gerber
 * Adolph Germer
 * Arturo Giovannitti
 * Benjamin Gitlow *
 * Carl Haessler *
 * Emanuel Haldeman-Julius SDL
 * Job Harriman
 * Michael Harrington DSOC
 * Hubert Harrison
 * Max S. Hayes
 * Bill Haywood IWW
 * Emil Herman
 * George D. Herron
 * Morris Hillquit ISS
 * Daniel Hoan
 * Darlington Hoopes SPUSA
 * Jessie Wallace Hughan ISS
 * Haim Kantorovitch
 * David Karsner
 * Helen Keller
 * Charles H. Kerr
 * George R. Kirkpatrick
 * Alexandra Kollontai
 * Antoinette Konikow *
 * Frederick Krafft
 * Maynard C. Krueger
 * William F. Kruse *
 * Leo Krzycki
 * Harry W. Laidler ISS
 * Algernon Lee ISS, SDF
 * Lena Morrow Lewis SDF
 * Walter Lippman
 * Jack London ISS
 * George Lunn
 * Theresa S. Malkiel
 * Mary Marcy
 * James H. Maurer SDF
 * Jasper McLevy SDF
 * David McReynolds SPUSA
 * Walter Thomas Mills
 * Tom Mooney
 * Thomas J. Morgan
 * Gustavus Myers
 * Scott Nearing
 * Reinhold Niebuhr
 * Santeri Nuorteva
 * Kate Richards O'Hare
 * James Oneal SDF
 * Mary White Ovington
 * Joseph Arthur Padway
 * Jacob Panken
 * Patrick L. Quinlan
 * A. Philip Randolph SDF, SDUSA
 * John Reed *
 * Victor Reuther DSOC
 * Walter Reuther
 * Charles Edward Russell
 * Bayard Rustin SDUSA
 * Carl Sandburg
 * Margaret Sanger
 * Roland D. Sawyer
 * Clarence Senior
 * Max Shachtman
 * Abraham Shiplacoff
 * Upton Sinclair ISS
 * John W. Slayton
 * John Spargo SDL
 * Seymour Stedman
 * Charles P. Steinmetz
 * A.M. Stirton
 * J.G. Phelps Stokes ISS, SDL
 * Rose Pastor Stokes *
 * Maurice Sugar
 * Norman Thomas
 * Henry M. Tichenor
 * Hermon F. Titus
 * Gus Tyler
 * Ernest Untermann
 * Charles H. Vail
 * Baruch Charney Vladeck
 * Alfred Wagenknecht *
 * Louis Waldman SDF
 * Julius Wayland
 * George W. Woodbey
 * John M. Work
 * Frank P. Zeidler SPUSA

Annotated list
Key:
 * * Went on to join the Communist Party, Communist Labor Party of America or Workers Party of America
 * ISS A founder or key member of the Intercollegiate Socialist Society, 1905, later League for Industrial Democracy
 * IWW A founder of the Industrial Workers of the World, 1905.
 * SDL Left to found the Social Democratic League of America, 1917.
 * SDF Left to found the Social Democratic Federation, 1936.
 * SDUSA Continued into Social Democrats, USA, 1973
 * SPUSA Went on to join the Socialist Party USA, 1973
 * DSOC Went on to join the Democratic Socialist Organizing Committee, 1973, later Democratic Socialists of America


 * Martin Abern *
 * Devere Allen
 * Elmer Allison *
 * E.B. "Harry" Ault
 * J. Mahlon Barnes
 * David P. Berenberg
 * Victor L. Berger, Congressman from Milwaukee
 * Barney Berlyn
 * Allan L. Benson, 1916 candidate for Vice-President
 * Ella Reeve Bloor *
 * Roy E. Burt
 * Frank Bohn IWW
 * Earl Browder *, Communist Party leader and presidential candidate
 * James P. Cannon *, leader of the Communist Party and Socialist Workers Party
 * Jack Carney
 * Travers Clement
 * Joseph Coldwell
 * James Connolly, Irish labor and nationalist leader
 * Eugene V. Debs IWW, labor organizer, Presidential candidate
 * David Dubinsky, labor leader
 * Max Eastman *, writer
 * J. Louis Engdahl
 * William M. Feigenbaum, New York assemblyman 1918
 * Elizabeth Gurley Flynn *, IWW and Communist leader
 * William Z. Foster *, Communist leader and presidential candidate
 * Louis Fraina *
 * Joseph Freeman *
 * Samuel Friedman, Vice-presidential candidate
 * Charles B. Garfinkel, New York assemblyman 1918, temporary chairman of the NYC central committee SPA in 1935 after Old Guard was expelled
 * Julius Gerber
 * Adolph Germer
 * Arturo Giovannitti
 * Benjamin Gitlow *
 * Carl Haessler *
 * Emanuel Haldeman-Julius SDL
 * Job Harriman, Vice-presidential candidate
 * Michael Harrington DSOC, author
 * Hubert Harrison
 * Max S. Hayes, labor leader
 * Bill Haywood IWW
 * Emil Herman
 * George D. Herron
 * Morris Hillquit ISS, labor lawyer, New York mayoral candidate
 * Daniel Hoan, mayor of Milwaukee
 * Darlington Hoopes SPUSA
 * Jessie Wallace Hughan ISS
 * Henry Jager, NY assemblyman 1921
 * Haim Kantorovitch
 * William KarlinSDF, lawyer, NY assemblyman 1918
 * Helen Keller
 * Charles H. Kerr, publisher
 * George R. Kirkpatrick
 * Antoinette Konikow *
 * Frederick Krafft
 * Maynard C. Krueger
 * William F. Kruse *
 * Leo Krzycki, chairman
 * Harry W. Laidler ISS
 * Algernon Lee ISS, SDF
 * Walter Lippman, journalist
 * Jack London ISS
 * Meyer London, Congressman from New York City
 * George R. Lunn, mayor of Schenectady, New York
 * Theresa S. Malkiel
 * Mary Marcy
 * James H. Maurer SDF
 * Jasper McLevy SDF, mayor of Bridgeport, Connecticut
 * David McReynolds SPUSA, peace advocate, SPUSA presidential candidate
 * Herbert M. Merrill, secretary of the SPA-NY, first Socialist New York assemblyman (1912)
 * Walter Thomas Mills
 * Tom Mooney
 * Thomas J. Morgan
 * Gustavus Myers
 * Scott Nearing
 * Reinhold Niebuhr, theologian
 * Santeri Nuorteva
 * Kate Richards O'Hare
 * James Oneal SDF
 * Mary White Ovington, co-founder of the NAACP
 * Joseph Arthur Padway
 * Jacob Panken, New York municipal judge
 * A. Philip Randolph SDF, SDUSA, labor and civil rights leader
 * John Reed *, author
 * Victor Reuther DSOC, labor organizer
 * Walter Reuther, labor organizer
 * Elmer Rosenberg, New York assemblyman 1918
 * Charles Edward Russell, writer
 * Bayard Rustin SDUSA, civil rights organizer
 * Carl Sandburg, poet
 * Margaret Sanger, advocate of family planning
 * Roland D. Sawyer
 * Edmund Seidel, New York state senator 1921–1922
 * Clarence Senior
 * Max Shachtman
 * Abraham I. Shiplacoff, NY assemblyman 1916, 1917, 1918
 * Upton Sinclair ISS, writer, organized End Poverty in California (EPIC)
 * John W. Slayton
 * John Spargo SDL, writer
 * Seymour Stedman
 * Charles P. Steinmetz, physicist
 * A.M. Stirton, publisher of The Wage Slave, candidate for governor in Michigan in 1908
 * J.G. Phelps Stokes ISS, SDL, social reformer
 * Rose Pastor Stokes *, social reformer
 * Maurice Sugar
 * Norman Thomas, peace advocate, Presidential candidate
 * Henry M. Tichenor
 * Hermon F. Titus
 * Gus Tyler, writer and labor leader
 * Ernest Untermann
 * Charles H. Vail
 * Baruch Charney Vladeck
 * Alfred Wagenknecht *
 * Louis Waldman SDF
 * Julius Wayland, publisher of The Appeal to Reason
 * Joseph A. Whitehorn, lawyer, New York assemblyman 1917, 1918
 * George W. Woodbey, preacher and African-American leader
 * John M. Work
 * Frank P. Zeidler SPUSA, mayor of Milwaukee, SPUSA presidential candidate