John O'Malley is a prominent American historian known for his work on the history of the Catholic Church and its influence on society. He has authored several influential books, including A History of the Popes and The First Jesuits, which explore the development of religious institutions and their impact on culture and politics. O'Malley is also a professor at Georgetown University, where he teaches courses on church history and theology. His research often focuses on the Counter-Reformation and the role of the Jesuits in shaping modern education and religious thought. His contributions have made significant impacts in both academic and religious communities.