Jason Casellas specializes in American politics, with specific research and teaching interests in American politics, legislative politics, and state and local politics. He is the author of Latino Representation in State Houses and Congress (New York: Cambridge University Press.) and Shifting Allegiances: The Election of Latino Republicans to State Legislatures and Congress (New York: Cambridge University Press Elements Series in American Politics) 

He is the recipient of numerous fellowships and awards, including a Princeton University Fellowship, an American Political Science Association Fellowship, a Ford Motor Company Fellowship, the Samuel DuBois CookPostdoctoral Fellowship at Duke University, and a United States Studies Centre Postdoctoral Fellowship at the University of Sydney (Australia).  His work has appeared in the Journal of Politics, Legislative Studies Quarterly, Political Research Quarterly, and other peer-reviewed journals.