Who was the First Lady to take a role as an active reformer?

Eleanor Roosevelt is often regarded as the first First Lady to take an active role as a reformer. During her husband Franklin D. Roosevelt's presidency, she advocated for civil rights, women's rights, and social justice issues, using her platform to influence public policy and raise awareness about social issues. She held press conferences, wrote a daily newspaper column, and traveled extensively to promote her causes, significantly redefining the role of First Lady in American politics.