Loewentheil’s research has focused on three areas: urban policy, especially housing and transportation; environmental policy and politics; and more recently, broader areas of economic policy including manufacturing, innovation and infrastructure. He has pursued work in these areas through a variety of civic organizations. As a college student, he founded the Roosevelt Campus Network, a national organization that engages young people in progressive politics through public policy. He served as executive director of Roosevelt from 2007-2009. During those years and up through the current day he has sat on numerous nonprofit boards, including the College Democrats of America Alumni Assoication, the Elmseed Enterprise Fund and the New Leaders Council. He also joined various advisory boards including the Drum Major Institute and, more recently, PolicyMic.com.