Jeffrey A. Singer is a senior fellow at the Cato Institute and works in the Department of Health Policy Studies. He is President Emeritus and founder of Valley Surgical Clinics Ltd., the largest and oldest group private surgical practice in Arizona, and has been in private practice as a general surgeon for more than 35 years.

He is also a visiting fellow at the Goldwater Institute in Phoenix. Singer is a member of the Board of Scientific Advisors of the American Council on Science and Health. From 1994 to 2016, he was a regular contributor to Arizona Medicine, the journal of the Arizona Medical Association. He served on the Advisory Board Council of the Center for Political Thought and Leadership at Arizona State University from 2014 to 2018 and is an adjunct instructor in the Program on Political History and Leadership at ASU. He writes and speaks extensively on regional and national public policy, with a specific focus on the areas of health care policy and the harmful effects of drug prohibition.