This is an archival study of Frederic Siedenburg, SJ, a Jesuit, who founded the first Catholic-Jesuit School of Social Work in the United States at Loyola University of Chicago in 1914. This study examines the multi-faceted career of this sociologist who served at two Catholic universities from 1914 through the 1930s when Progressivism and the New Deal in the United States were attempts to deal with social reform; the Catholic Church, in a variety of ways, responded to these reform efforts. Siedenburg espoused Catholic social teaching and attempted to carry out its tenets within a Catholic context as an educator and administrator, a social theorist and social activist. He was also an ecumenist and known for his reaching out and engaging in dialogue with other religious bodies.