Karch is a lecturer in social studies and in the Freshman Seminar Program at Harvard, where he offers courses on modern European history. He is broadly interested in issues of ethnic identity and minority policy in modern Central Europe, especially former Habsburg and German borderlands. Karch received his PhD in history from Harvard in May 2010, with a dissertation on nationalism and national indifference in Upper Silesia, along the German-Polish border, from 1848–1960.