Hamburger is the Maurice and Hilda Friedman Professor of Law at the Columbia University School of Law. He is a legal historian and a scholar of constitutional law. Before moving to Columbia, Hamburger was John P. Wilson Professor at the University of Chicago Law School, where he was also Director of the Bigelow Program and the Legal History Program. He was previously Oswald Symyster Colclough Research Professor at George Washington University Law School and, before that, he taught at the University of Connecticut Law School. He has been a visiting professor at the University of Virginia Law School and was the Jack N. Pritzker Distinguished Visiting Professor of Law at Northwestern Law School. Early in his career, he was an associate at the law firm of Schnader, Harrison, Segal & Lewis LLP in Philadelphia.
Hamburger is a leading scholar of the First Amendment who "made a valuable contribution to our knowledge of Jefferson's thinking and actions with respect to matters of church and state". He is known for arguing that "the First Amendment, originally thought to limit the government, has been increasingly interpreted by the Court to mean limiting religion and confining it to the private sphere."
Fruchtman, reviewing Law and Judicial Duty (2008), says it, "is by any definition ground-breaking. It is a creative, magisterial contribution to our understanding of judicial review and an independent judiciary."
Justice Hugo Black, who served on the Supreme Court 1937 to 1971, came under attack from Hamburger who argues that Black's views on the need for separation of Church and State were deeply tainted by prominent roles in the Ku Klux Klan, a vehemently anti-Catholic organization. Hamburger relies on Black's biographers who say he was a KKK member and actively campaigned for Senate in 1926 at nearly all of Alabama's 148 KKK Klaverns, where he attacked the Catholic Church. Biographer Newman quotes his campaign manager as saying Black "could make the best anti-Catholic speech you ever heard."