[6] By the mid-1970s, he had become a professor of political science at Catholic University in Washington, D.C., and was establishing a reputation as an expert on the United States Congress.

[7] Ornstein studies American politics and is a frequent contributor to The Washington Post and many magazines, such as The Atlantic and the National Journal.

[8] He wrote a weekly column for Roll Call from 1993 until April 10, 2013, and was co-director, along with Thomas E. Mann, of the AEI-Brookings Election Reform Project.

[10] Ornstein is a member of the advisory board of the Future of American Democracy Foundation,[11] a nonprofit, nonpartisan foundation in partnership with Yale University Press and the Yale Center for International and Area Studies "dedicated to research and education aimed at renewing and sustaining the historic vision of American democracy".

Foreign Policy named Ornstein, along with Thomas E. Mann, one of its 2012 Top 100 Global Thinkers "for diagnosing America's political dysfunction".