Sanford Levinson received a bachelor's degree from Duke University, a law degree from Stanford University, and a PhD degree from Harvard University. At one point he was a member of the department of Politics at Princeton. Levinson taught law at Georgetown, Yale, Harvard, New York University, Boston University, the University of Paris II, Central European University in Budapest, and the Hebrew University in Jerusalem. In 2001, Levinson was elected to the American Academy of Arts and Sciences. In 2010, he was given the Lifetime Achievement Award by the Law and Courts Section of the American Political Science Association. In 1980, he joined the University of Texas School of Law at Austin, Texas where he is also a professor of government at Texas. He holds the W. St. John Garwood and W. St. John Garwood, Jr. Centennial Chair in Law.

Levinson is quoted often in publications about numerous topics involving law. Levinson has described himself as a "a card-carrying A.C.L.U. member who doesn't own a gun" who has argued that the Second Amendment of the United States Constitution limits the government's authority to regulate private gun ownership. Levinson's opinions on Constitutional Law have been reported in the media including his opinions about Second Amendment cases. Levinson has been a panelist on programs sponsored by the Association of American Law Schools and has spoken on topics alongside prominent lawyers such as Kenneth W. Starr. Levinson has been identified as a "prominent liberal law professor" and been grouped with other professors including Laurence H. Tribe of Harvard and Akhil Reed Amar of Yale. Levinson's opinion has been cited during the nominating process for Supreme Court nominees.

Levinson has been critical of Supreme Court justices who have stayed in office despite medical deterioration based on longevity; for example, Levinson criticized Chief Justice William H. Rehnquist for a "degree of egoistic narcissism" by declaring six weeks before his death of his intention to stay on. Levinson has called for term limits for Supreme Court justices along with a growing list of "scholars across the ideological spectrum." He has published comments critical of life tenure for Supreme Court justices.

Levinson is particularly noted for his "seminal article" in the Yale Law Journal entitled The Embarrassing Second Amendment. He argued that the Second Amendment doesn't offer either gun rights or gun control advocates a refuge. He argued "society must decide the issue of gun control on practical as well as on constitutional grounds ... the issue is to what extent does the Second Amendment permit the Government to do what it wants in controlling firearms, just as we have to establish the extent to which it can limit speech or break into your house without a warrant. Levinson has criticized liberal lawyers as treating "the Second Amendment as the equivalent of an embarrassing relative whose mention brings a quick change of subject." He has argued that the Constitution protects some personal ownership of firearms but admits that "courts are likely to rule that Congress can do almost anything short of an outright prohibition of owning guns."

Levinson taught a course called Torture, Law and Lawyers at Harvard Law School in 2005. Levinson has written essays in The New York Times. Levinson edited Torture: A Collection (2005). A reviewer commented: "What's most striking about these essays is that despite their abstract and theoretical content, they generally do not contradict the depiction of actual interrogators described by Mackey and Miller. The wall between the liberal campus and a conservative, utilitarian-minded military breaks down because the questions are so serious that few of this book's contributors want to engage in polemics, and few -- to their credit -- ever seem completely comfortable with their own conclusions."

Levinson has been a critic of the unitary executive and excessive presidential power. In the magazine Dissent, he argued that “constitutional dictators have become the American norm." Presidents "have an incentive to declare emergencies” and assume “quasi-dictatorial powers," wrote Levinson. Levinson was highly critical of president George W. Bush who he regarded as possibly the "absolutely worst president." Levinson notes that President Obama seems likely to repeat the pattern of expansive presidential power. He wrote an essay titled “Are we electing a constitutional dictator?” in which he criticized a system which allows presidents to make dictatorial decisions of great consequence without providing ways to discipline those who display bad judgment. Levinson commented about a ban on gay marriage proposed by former President George W. Bush in legal terms as a Constitutional issue.

Levinson has criticized the Constitution for what he considers to be numerous failings, including an inability to remove a president despite lack of confidence by lawmakers and the public, the president's veto power as being "extraordinarly undemocratic", lack of representation in the Senate for highly populated states such as California. He also criticizes the primary process in which important states which aren't considered "battleground states" are ignored by presidential candidates. He's often called for a Second Constitutional Convention: "We ought to think about it almost literally every day, and then ask, 'Well, to what extent is government organized to realize the noble visions of the preamble?' That the preamble begins, 'We the people.' It's a notion of a people that can engage in self-determination." Levinson's book Our Undemocratic Constitution: Where the Constitution Goes Wrong (and How We the People Can Correct It) calls for "wholesale revision of our nation's founding document."

Levinson appeared on the Bill Moyers television program in 2007. Levinson's research interests include American Constitutional development, Constitutional design, law, religion, multiculturalism, society, and theories of Constitutional Interpretation. Levinson participates in a blog called Balkinization which focuses on constitutional, First Amendment, and other civil liberties issues as well as a blog called Our Undemocratic Constitution. With Jeffrey K. Tulis, he is co-editor of the Johns Hopkins Series in Constitutional Thought.