In 1966, Professor Levasseur obtained an M.C.L. from Tulane University where he returned to teach in 1968. In 1969, he was an associate with the Paris firm of Mudge, Rose, Guthrie & Alexander but left the firm to become a technical assistant at the World Bank in Washington, D.C. In the fall of 1970, he resumed teaching at Tulane until 1977. Professor Levasseur joined the Law Center faculty in 1977. In 1998, the Université d’Aix Marseille Paul Cézanne bestowed on Professor Levasseur the degree of Doctor of Laws Honoris Causa. In January 2010, Professor Levasseur received a second Doctorate Honoris Causa, this one from the Université de Paris Panthéon Assas. He maintains an active membership in the International Academy of Comparative Law, the American Association for the Comparative Study of Law, the Société de Législation Comparée, the Association Henri Capitant and the International Association of Legal Methodology.

Professor Levasseur is a member of several boards, including the Fondation pour le Droit Continental, the Revue Internationale de Droit Comparé, E-Competition, the Revue Trimestrielle de Droit Civil, El Foro de Derecho Mercantil, the American Journal of Comparative Law, the LSU Center for French and Francophone Studies.

His areas of expertise are Legal Traditions, particularly Civil Law Systems, the Civil Law of Obligations, Comparative Law of Contracts, Comparative aspects of EU and U.S. Law, EU/EC Law, International Trade, Louisiana Sale/Lease and Quasi-Contracts.