Prior to joining the faculty in 1969 Mr. Picker practiced law in Los Angeles and then was on the staff of USTR ("United States Trade Representative") during the so-called "Kennedy Round" of GATT Trade Negotiations, and later in the General Counsel's office of Eximbank, both in Washington. His primary areas, on coming to the law school, were international law, international trade, and international negotiations. He was the founder, initial U.S. Director, and Advisory Board Chair of the Canada-U.S. Law Institute which is jointly operated by CWRU and the University of Western Ontario, and he served as the first Director of what is now the Frederick K. Cox International Law Center. In his later years he established the Russian Legal Studies Program at the law school, and on behalf of the Ohio Bar he served as Chair of the League of Ohio Law Schools Committee on Evaluation of Foreign Education for the Ohio Supreme Court.

In addition to his activities at the law school Mr. Picker has had wide experiences abroad. He served on the first NAFTA Chapter 20 dispute resolution panel in a case brought by the United States against Canada in 1996. In 1995 he served as consultant to The World Bank on Russian legal education as part of a World Bank legal reform loan to Russia. He has also served on the boards of such nonprofit organizations as the Washington-based SALS ("Southern African Legal Services") Foundation and ACSUS ("Association for Canadian Studies in the United States"). Mr. Picker was a also a member of the first ABA international trade visits to the Soviet Union in 1973 and to the People's Republic of China in 1979. He was awarded two Fulbright Grants to Australia, in 1968 and 1985, to teach and research on Pacific Basin trade and on East-West Trade. He served as scholar in residence at the Legal Resources Centre in South Africa in 1980, and he has taught and lectured at Westminster University in London, Universidad Gama Filjo in Brazil, and at the law faculties of St. Petersburg State University, Novgorod State University and Volgograd State University, all in Russia.

Mr. Picker was responsible for bringing the first U.S. Supreme Court and Canadian Supreme Court justices to CWRU Law School (Justice Potter Stewart and Brian Dixon, respectively, in 1980) as well as the first World Court American and Russian judges to the Law School (Judge Stephen Schwebel and Judge Vladlen Vereshchetin, respectively), and he organized the first National Security Law course to be taught at the law school by the then sitting General Counsel of the CIA, Elizabeth Rindskopf who commuted weekly from Washington to Cleveland.

In 2002, in recognition of his work on behalf of Russian legal Education, Prof. Picker together with his wife, Prof. Jane Picker, were awarded Honorary Doctorate of Laws degrees by St. Petersburg State University, St. Petersburg, Russia. They are the only Americans to be awarded such degrees and the only husband and wife of any nationality to be awarded such degrees in the almost 300 year history of the university which was founded by Peter the Great.

Since retiring in 2002 Mr. Picker has served as President of RUSLEF ("Russia-United States Legal Education Foundation"), a public interest nonprofit organization he founded together with his wife, Jane Picker, to foster a rule of law legal culture in Russian legal education. RUSLEF's principal activity is to bring Russian law students for a year's study at law schools throughout the U.S.