His professional career is mainly focused in the advocacy; in fact he is a Legal representative of la Junta de Castilla y León from 2001 October and also manages the legal Service of Delegation of the Junta de Castilla y León in Segovia since then. He has a wide public law background as he is an Associate Professor of Tax Law in the Universidad de Valladolid (ES) since2004 October and also teaches in the Master of International Legal Practice of the Law School of Instituto de Empresa and in the Business degree in the IE University. He has been Visiting Scholar in the University of San Diego in 2010. He has taught administrative proceeding in special courses for government employees in the Escuela de la Función Pública de Castilla y León from the year 2004 to 2009. Marco Sandulli has collaborated in several books related to the Public law. He participated in the book “Comentarios a la Ley 3/2001 de Gobierno de Castilla y León” published by the Función Pública magazine, in “Manual de Derecho Público de Castilla y León published by LEX NOVA and in “Comentarios al Estatuto de Autonomía de Castilla y León ” Publisher by ARANZADI. He has been a member of the Executive Committee of the Letrados de la Junta de Castilla y León Association and also has collaborated in the commission of codification of the regulation of development of the Law 6/2003 de Asistencia Jurídica a la Comunidad de Castilla y León.