Gennaro was admitted to the Monza Bar in 1986, to the Supreme Court in 1998 and to the Register of Auditors in 1997.
After many years of experience, in civil and corporate law, at the Law Firm of Prof. Avv. Cesare Fabozzi and Prof. Avv. Ugo Carnevali, and in tax matters at the "Studio Legale Tributario Biscozzi - Fantozzi" and the “Studio Legale e Tributario Arpano Bonafè Grifoni”, in 2011 he founded the "Studio Legale e Tributario Arpano", giving advises to individuals and companies in tax, corporate and commercial law, as well as in tax and criminal-tax litigation, even before the Supreme Court.
He developed a strong experience in relations with the Public Authorities, assisting clients during tax audits and in the subsequent out-of-court phase of comparison with the Tax Authorities. He is the author of numerous specialized scientific publications on tax and corporate law, as well as being a speaker at various conferences on tax law.