He is an author of the nation’s leading casebook on Civil Procedure. He also is the author of Redefining the Supreme Court's Role: A Theory of Managing the Federal Court System (a treatment of the Supreme Court's case selection process) in addition to several other books, numerous chapters, articles and Supreme Court briefs.

He holds honorary degrees from Fordham University, Saint Francis College, Hamilton College, Iona College New York, Saint John's University, University of Rochester, Yeshiva University, Katholieke Universiteit Leuven, University of Surrey and University of Warwick. The student editors of NYU's Annual Survey of American Law dedicated their Volume 60 in his honor. He was named by Emory University "Outstanding High School Debate Coach of the Last 50 Years" for work he did from 1960-1975. He has been honored at the Harvard Law Review Annual Banquet, and has been named "Alumnus of the Year" both at Fordham and at his high school, Brooklyn Prep. In July 2008 he was named a Chevalier de la Légion d'Honneur, the national order of the Legion of Honor of France.

Before coming to NYU, President Sexton served as Law Clerk to Chief Justice Warren Burger of the United States Supreme Court (1980-1981), and to Judges David Bazelon and Harold Leventhal of the United States Court of Appeals (1979-1980). For ten years (1983-1993), he served as Special Master Supervising Pretrial Proceedings in the Love Canal Litigation. From 1966 - 1975, he was a Professor of Religion at Saint Francis College in Brooklyn, where he was Department Chair from 1970-1975.