Addams argued for a separate legal system for juveniles that would guide and teach them the proper way to behave rather than just locking them away in jails. Some supported the idea for the sake of the children, while others feared the growing number of immigrant street youth in Chicago in the late nineteenth century. In spite of the fears, Illinois became the first state to establish a separate court system for juveniles in 1899.
In the new juvenile courts, specially trained judges had enormous flexibility to act on a child's behalf, taking over for parents. The law defined a juvenile as a person less than sixteen years of age. Rather than prosecute a juvenile for a crime, the court would place the juvenile in a reform school or with foster parents. These juveniles remained under court supervision until the of age twenty-one. By 1925 almost all of the states had juvenile systems, using Illinois as a model.
As her reputation and influence grew, Addams was drawn into greater areas of civic responsibility. In 1905 she was appointed to Chicago's Board of Education. When the National Association for the Advancement of Colored People (NAACP) was formed in 1909, Addams was a member of its executive committee. The NAACP became a champion of justice for minorities. Also in 1909, Addams became the first woman to be elected president of the National Conference of Charities and Correction, later known as the National Conference of Social Work. In 1911 she became the first head of the National Federation of Settlements, an organization she remained a part of until she died.