Dean Rossner holds a J.D. and M.A. from a joint program in law and philosophy at the University of Michigan, where he was named to the Order of the Coif. He clerked for Judge Nathaniel R. Jones, U.S. Court of Appeals for the Sixth Circuit, then joined the U.S. Department of Justice Antitrust Division where he prosecuted criminal antitrust and Department of Defense contract fraud cases as well as handled merger and other civil and administrative antitrust matters. In 1986, he served as an assistant U.S. attorney in the U.S. Attorney's Office for the District of New Jersey, where he prosecuted white-collar crime cases, including government contract fraud, government program fraud, and tax and securities fraud. In 1991, he joined the New Jersey Attorney General's Office as chief of the Antitrust and Securities Fraud Unit in the Division of Criminal Justice. Within the Division of Criminal Justice, he subsequently served as chief of the Official Corruption and Antitrust Bureau, chief of the Financial Crimes and Antitrust Bureau, deputy director and then acting director of the division.

Dean Rossner has been active in the National Association of Attorneys General (NAAG) Antitrust Task Force, serving for almost 10 years as vice chair for litigation training and before that as a vice chair for investigations. NAAG recognized his achievements by awarding him the NAAG Marvin Award for outstanding leadership, experience and achievement in advancing the work of state attorneys general and also the first NAAG Training Institute Teacher of the Year Award.

With more than 27 years of teaching litigation advocacy, in 2001, he was founding director of the New Jersey Attorney General's Advocacy Institute, which has become a national model for training public sector attorneys. He has developed curricula and course and teaching materials on trial advocacy skills, deposition skills, examination of experts skills, and evidentiary issues at trial, as well as various substantive legal issues relating to the work of government attorneys. Since 1988, he has served as a faculty member and lecturer for the National Institute of Trial Advocacy (NITA), teaching at NITA's regional, national, and in-house programs. He has also authored course and teaching materials for numerous NITA-style programs, and collaborated with professional and other organizations to develop and conduct specialized courses for attorneys.

Dean Rossner has previously taught at Temple Law School, Seton Hall Law School, and Rutgers School of Criminal Justice as well as at the Rutgers School of Law-Newark. He currently teaches antitrust, intensive trial advocacy, evidentiary issues at trial, intensive deposition advocacy and courses in the Institute for Professional Education. He serves on the New Jersey Supreme Court Committee on the Rules of Evidence and is president of the C. Willard Heckel Inn of Court.