After graduating from Cornell Law School summa cum laude, Professor O’Sullivan clerked for Chief Judge Levin Campbell of the United States Court of Appeals for the First Circuit and then for Justice Sandra Day O’Connor of the United States Supreme Court. She spent five years with Davis Polk & Wardwell in New York, where she worked on mergers and acquisitions litigation as well as white-collar criminal defense matters. Her experience at Davis Polk included work on U.S. v. REI, a lengthy and complex public corruption case, and the BCCI case, where she worked with Robert Fiske in the defense of First American Bank, Clark Clifford, and Robert Altman. In 1991, Professor O’Sullivan joined the Criminal Division of the United States Attorney’s Office for the Southern District of New York as an Assistant United States Attorney. There, she spent most of her time prosecuting major white-collar crimes. She and another AUSA successfully prosecuted the largest bank fraud case in the country at the time and the first to be brought under the financial kingpin statute. Professor O’Sullivan was then recruited by Robert Fiske, the newly appointed independent counsel for the Whitewater investigation, to join his staff in Little Rock, Arkansas, as associate counsel. She worked for Mr. Fiske, and briefly for Ken Starr, before commencing her teaching career at Georgetown in 1995. Also in 1995, on appointment by the Supreme Court, she successfully briefed and argued a case on behalf of an indigent petitioner in a case pending before that Court.
Professor O’Sullivan has written many articles and the leading casebook on white-collar crime and is a recognized expert on both the federal sentencing guidelines and white collar criminal law. Professor O’Sullivan is increasingly interested in the subject of cross-border criminality and law enforcement. With Professors David Luban and David Stewart, she published a casebook on International and Transnational Criminal Law. She has taught international criminal law in London and Dublin as well as Georgetown. In 2010, she served as a visiting professional at, and then a consultant for, the Office of the Prosecutor of the International Criminal Court.
Professor O’Sullivan is a member of the American Law Institute and has served as a member of, and reporter for, such projects as the ABA’s revision of the Standards for Criminal Justice on Guilty Pleas and the U.S. Sentencing Commission’s Ad Hoc Advisory Group on the Sentencing Guidelines applicable to Organizations.
"Why a Ruling Declaring Trump ‘Likely’ Broke Laws May Not Mean He Will Be Prosecuted," coverage in The New York Times, March 29, 2022, featuring Professor Julie O’Sullivan.
"Julie O’Sullivan on Corporate Crime and Corporate Power," coverage in Corporate Crime Reporter, November 30, 2021, featuring Professor Julie O’Sullivan.
"The land was worth millions. A Big Ag corporation sold it to Sonny Perdue's company for $250,000," coverage by The Washington Post, June 29, 2021, featuring Professor Julie Rose O'Sullivan.
"‘Never Seen Anything Like This’: Experts Question Dropping of Flynn Prosecution," coverage by NPR, May 7, 2020, quoting Professor of Law Julie O’Sullivan.