Casey B. Mulligan is an American economist and author. He is a professor in economics at the University of Chicago. He served as chief economist for the Council of Economic Advisers in the Trump Administration from September 6, 2018, to August 2019. Mulligan also served as Chief Counsel for Advocacy at the Small Business Administration from August 5, 2025 until April 2026 under the second Trump Administration. In April 2026, Secretary of Health and Human Services Robert F. Kennedy Jr. appointed Mulligan as the Chief Economist and Regulatory Officer at the Department of Health and Human Services.