Matthew Steilen is Professor of Law and an Affiliated Faculty Member in the Department of Philosophy, College of Arts and Sciences. He holds a J.D. from Stanford Law School and a Ph.D. in Philosophy from Northwestern University, where he wrote a dissertation in contemporary metaphysics under Charles Travis, and was a University Fellow and a Searle Center Teaching Fellow. After graduating from Stanford, Steilen served as a law clerk to the Honorable Kermit V. Lipez of the United States Court of Appeals for the First Circuit. He was a member of the California Bar and was associated with the law firm of Covington & Burling LLP, where he practiced in civil litigation and did substantial pro bono work in the area of constitutional rights.

Steilen teaches and writes in the areas of constitutional law and legal history. At UB, he has taught Constitutional Law, Federal Courts, Administrative Law, Complex Litigation, and Civil Procedure, as well as seminars on administrative history and history of the common law. His central research interest is the development of legal institutions and ideas. His articles have examined judicial review, due process, royal prerogative, presidential powers of non-enforcement, constitutional conventions, and legislative attainders in New York, Pennsylvania, and Virginia during the American Revolution, among other topics. His work has appeared in peer-reviewed journals, including Law and History Review and Legal Theory, and been selected for inclusion in the Harvard/Stanford/Yale Junior Faculty Forum and the Law and Humanities Junior Scholar Workshop.

Steilen has been a visiting legal scholar at the Institute for Legal Studies at the University of Wisconsin and was twice awarded a short-term fellowship to conduct research at the International Center for Jefferson Studies at Monticello. In 2024, he was a visitor at the Faculty of Law, Cambridge University..