Guglielmo Maisto founded Maisto e Associati in 1991. He is a Professor of international and comparative tax law at the Università Cattolica di Piacenza. He is President of the Italian Branch of the International Fiscal Association (IFA), member of the Board of Trustees of the International Bureau of Fiscal Documentation (IBFD) in Amsterdam, member of the Advisory Board of the Master of Advanced Studies in International Taxation of the Lausanne University, member of the Practice Council of the International Tax Program of New York University's (NYU) School of Law and member of the Board of the American Chamber of Commerce in Italy. He represents the Italian Association of Industries (Confindustria) at the OECD Business Industry Advisory Committee in Paris.
He acted as a consultant to the Ministry for European Community Affairs and was a member of the EU Joint Transfer Pricing Forum. He is a member of several law societies and of the editorial board of various Italian and foreign tax legal journals. He usually participates as speaker in several annual tax conferences.