Helen Marot was born in Philadelphia on 9th June, 1865. The daughter of wealthy Quakers, Marot worked as a librarian in Wilmington, Delaware, before returning to Philadelphia to open her own private library on social reform.
In 1903 Marot joined with Mary Kenney O'Sullivan, Jane Addams, Mary McDowell, Margaret Haley, Agnes Nestor, Florence Kelley and Sophonisba Breckinridge to form the Women's Trade Union League (WTUL). Marot became executive secretary of the WTUL New York branch.
Marot was the main figure in the formation of the Bookkeepers, Stenographers and Accountants Union and the the leader of the International Ladies' Garment Workers Union.
A Fabian socialist, in later life, Marot concentrated on writing and published several books including American Labor Unions (1914) and Creative Impulse in Industry (1918). She also worked for The Masses (1916-17) and The Dial (1918-20).
Helen Marot died on 3rd June, 1940.