After graduating from Northwestern University and Harvard Law School, he tried many felony cases as a prosecutor in the Cook County States' Attorney's Office in Chicago. A recipient of a Guggenheim Fellowship in Constitutional Studies, Professor Barnett has been a visiting professor at Penn, Northwestern and Harvard Law School.
Professor Barnett's publications includes twelve books, more than one hundred articles and reviews, as well as numerous op-eds. His most recent book is The Original Meaning of the Fourteenth Amendment: Its Letter and Spirit (Belknap Press, 2021) (with Evan Bernick).
In 2004, he argued the medical marijuana case of Gonzalez v. Raich before the U.S. Supreme Court. In 2012, he was one of the lawyers representing the National Federation of Independent Business in its constitutional challenge to the Affordable Care Act. Recently, he appeared on PBS's Constitution USA with Peter Sagal; and he portrayed a prosecutor in the 2010 science-fiction feature film, InAlienable.