Since 2000, Rosenfeld has taught at Fairfield University, where he offers courses on modern European History, German History, Holocaust History, Jewish History, Historical Memory, and Counterfactual History. During this period, he has published two dozen academic articles, five monographs, and two edited volumes, many of which examine how the memory of the Third Reich and Second World War has taken shape in western culture, especially in architecture, monuments, literature, film, television, and historiography. His 2015 book, Hi Hitler! How the Nazi Past is Being Normalized in Contemporary Culture (Cambridge University Press, 2015), won the German Studies Association's 2017 Sybil Halpern Milton Memorial Book Prize for the best book dealing with Nazi Germany and the Holocaust. Rosenfeld has also been a leading scholar in the field of counterfactual history, publishing books and articles about the growing importance of historical speculation in western culture. They include The World Hitler Never Made: Alternate History and the Memory of Nazism (2005), What Ifs of Jewish History (2016), "Why Do We Ask 'What If? Reflections on the Function of Alternate History" (2002). and "The Ways We Wonder 'What If?' Towards a Typology of Historical Counterfactuals" (2016). Rosenfeld's current research focuses on the history and memory of fascism in the United States. His essays on the topic include "An American Führer? Nazi Analogies and the Struggle to Explain Donald Trump" (2019) and "Donald Trump's Situational Fascism" (2021).
