My research project traces the emerging radical histories at three of Chicago’s Catholic universities during the Vietnam War: Loyola University, Mundelein College, and DePaul University. Published research on resistance to the Vietnam War at Catholic universities, specifically in Chicago, is largely overshadowed by substantial scholarship on the broader anti-war movement of the 1960s and 1970s. Unlike protests at secular institutions, Catholic universities were specially guided by religious faith in their approach to the Vietnam War. While the United States encountered revolutionary social change in the 1960s, the Catholic Church also experienced a dramatic transformation. The Second Vatican Council, or Vatican II, in the early 1960s acknowledged the Church’s commitment to social justice and recognized its potential as a global moral authority. Church officials also considered traditional teachings on war and violence within the context of Cold War ideology and nuclear proliferation. American Catholics embraced the radical changes unfolding in Rome, and implemented their renewed faith into discourse and action concerning contemporary global issues. As the Vietnam War escalated in the late 1960s, American Catholics responded with a zealous message of peace and justice evocative of their faith. Specifically, in Chicago, the universities and colleges of Loyola, Mundelein, and DePaul utilized the Church’s modernized moral codes to demonstrate their disapproval of the war. These university communities in Chicago applied their Catholic faith in discourse and action aimed at understanding the Vietnam War’s moral dilemmas. National events during the war, especially the Kent State massacre in 1970, also invigorated Chicago’s Catholic universities to sustain their moral opposition to the war. Their Catholic character challenged ROTC and the military draft’s contributions to the war, and demonstrated an active opposition to their presence on campus. Loyola, Mundelein, and DePaul resisted the Vietnam War under the guidance of a moral foundation that derived from their evolving Catholic identity in a post-Vatican II era.