O'Sullivan is a feature writer for The Bridge at the Mercatus Center at George Mason University and authors a a regular column on technology topics for Reason. Her work at the Mercatus Center focuses on cybersecurity, surveillance, Internet freedom, cryptocurrency, and the economics of technology. Her writing has been published in The Wall Street Journal , Chicago Tribune, Newsweek, The Washington Times, U.S. News & World Report , and other outlets. O'Sullivan is the co-author of two books, Liberalism and Cronyism: Two Rival Political and Economic Systems with Randall G. Holcombe and Bitcoin: A Primer for Policymakers with Jerry Brito. In 2016, she was selected as one of Forbes 30 Under 30 in policy.