Professor Celli Junior has more than 30 years of experience both as lawyer and consultant at reputable law firms in Brazil, as well as legal counsel and consultant for both domestic and transnational corporations mainly in the areas of Telecommunications Law (Anatel); International Law especially International Trade Law (WTO Law related matters, such as tariff barriers, non-tariff barriers, technical barriers to trade, trade remedies and trade in services, among others); Regional Trade Agreements (Mercosur); Foreign Investments; International transactions and contracts; and Antitrust Law.

Umberto Celli Junior is full professor of International Law at the University of São Paulo. He was also Dean of the University of São Paulo Faculty of Law at Ribeirão Preto campus from 2013 to 2017 an member of the Brazilian list of panelists at the WTO.