The famous social reformer instrumental in establishing the settlement house movement in America was Jane Addams. She co-founded Hull House in Chicago in 1889, promoting social reform and community assistance. Addams focused on improving immigrant lives, advocating for women's rights and education. Her efforts led to significant advancements in social work, emphasizing the need for community support and activism. Addams became a nationally recognized figure for her humanitarian contributions, receiving the Nobel Peace Prize in 1931, solidifying her legacy in American social reform.