O’Sullivan (Mary Kenney) is born in Hannibal, Missouri.

The daughter of Irish immigrants, Mary Kenney O’Sullivan becomes a bookbinder, moves to Chicago to organize women in the printing industry, and becomes the first female “general organizer” in the American Federation of Labor. Sent to Boston in 1892 by AFL president Samuel Gompers to organize workers, she marries John O’Sullivan, labor editor of the Boston Globe, in 1894, lives initially at Denison House, then moves to Worcester Square, where her home because a gathering place for activists and progressives. O’Sullivan helps to found the National Women’s Trade Union League in 1903.* She dies in Medford in 1943, and is buried in St. Joseph’s Cemetery in West Roxbury.