In 1909, Kelley helped create the National Association for the Advancement of Colored People (NAACP), and thereafter became a friend and ally of W. E. B. Du Bois.
In 1917, she again filed briefs in a Supreme Court case for an eight-hour workday, this time for workers "in any mill, factory or manufacturing establishment", in the case "Bunting v. Oregon" [REF].