Haselswerdt is a political scientist whose work focuses on the politics of public policy, particularly taxation, social policy and health policy. His past research examines the implications of policy delivery through the tax code (i.e., tax breaks) on both congressional politics and public opinion. Haselwerdt served as a Robert Wood Johnson Foundation Scholar in Health Policy Research at the University of Michigan. He worked on tax issues as an American Political Science Association Congressional Fellow in the office of U.S. Senator Charles Schumer, and worked as a lobbyist in Washington, DC for six years before making the change to academia. He received his PhD from George Washington University.