Caldwell joined the USC faculty in 1945 as a member of the Department of History specializing in Early American History, American Intellectual-Cultural History, and European-American Relations. In 1946, he also became Chair of the Department of General Studies in American Civilization and Institutions. His honorary and professional organization memberships included: The
American Historical Society; the
Mississippi Valley Historical Association;
Phi Kappa Phi (all-university national scholarship society);
Phi Alpha Theta (national history honor society);
Pi Kappa Delta (national speech and debate honor society);
Tau Kappa Alpha (national honor society in journalism and mass communications); and the
American Association of University Professors (AAUP). While on the USC faculty, Caldwell served as secretary and later president of the local chapter of the AAUP; president of what was renamed the Faculty Center after he successfully pressed for the merger of the Men's Faculty Club and the Women's Faculty Club; member of the University Faculty Senate; member of the University Committee on Directed Teaching; and faculty sponsor for numerous student organizations. He also served as president of the USC Retired Faculty Association in 1978–1979. He initiated and taught history classes in Europe during summer sessions. These courses combined travel with the study of European history and included interviews with leading European personalities involved in national and international affairs. (SOURCE: USC News Bureau, n.d.; from the USC University Archives). After formally retiring from USC, he was invited to create an institute for the study of U.S. presidential history at the
University of California, Santa Barbara, but he declined and taught courses part-time on journalism, law, and government at USC until his death. Among numerous students that he mentored, one,
Carole Shammas, now holds a chair in the Department of History at USC. His students also included football star
Frank Gifford, who recalled his girlfriend urging him to take Caldwell's course "Man and Civilization." == Political activism ==