Professor Sparr's scholarly work is focused on the twentieth century American Catholic experience and New York City history. His major contributions in these areas include: To Promote, Defend, and Redeem, The Catholic Literary Revival and the Cultural Transformation of American Catholicism, 1920-1960 (1990), a cultural history of American Catholicism before the Second Vatican Council, and "Looking for Rosie, Women Defense Workers in the Brooklyn Navy Yard, 1942-1946," New York History (July, 2000). He is co-winner of the Kerr History Prize (2001), awarded each year by the New York Historical society for the best article published in the association's quarterly, New York History.