Agnes Nestor was born in Grand Rapids, Michigan, on 24th June, 1880. In 1807 the moved to Chicago where she went to work in a glove factory.
Nestor became an active trade unionist and in 1898 emerged as one of the leaders during a ten day strike at her factory. In 1902 she helped form the International Glove Workers Union. The following year Nestor joined with Mary Kenney O'Sullivan, Jane Addams, Mary McDowell, Margaret Haley, Helen Marot, Florence Kelley and Sophonisba Breckinridge to form the Women's Trade Union League (WTUL).
Nestor held several senior posts in the International Glove Workers Union, including vice president (1903-1906 and 1915-38), secretary-treasurer (1906-1913), general president (1913-1915) and director of research and education (1938-1948).
Agnes Nestor died in Chicago on 28th December, 1948.