- D. in Law.
- Professor of Constitutional Law at the Complutense University (Madrid), since 1989.
- Visiting Professor at the University of Paris-2 (Panthéon-Assas, February, 2016).
- Deputy Director of the Spanish Centre for Political and Constitutional Studies (CEPC) in two different periods (August 2002- September 2004 and February 2012-November 2015).
- Member of the staff in the Cabinet of the Spanish Prime Minister (Department of Parliament and Institutions, 2000-2002).
- Substitute (Spanish) Member of the Commission for Democracy through Law of the Council of Europe (Venice Commission) in two different periods (2004-2009, and 2012-2014).
- Member of the Scientific Committee of the Fondation Robert Schuman (Paris), since 2005.
- (Since october, 2014): Senior Leader of a 24-months Twinning contract (Chef de Projet senior du contrat de jumelage MA13/ENP-AP/OT31, “Reinforcement des capacités organisationnelles et techniques de la Délégation Interministérielle aux Droits de l’Homme (DIDH) du Royaume du Maroc”), funded by the European Union.
Author of six books on constitutional matters (parliamentary law, electoral law, the Spanish political transition, constitutional proceedings and the Council of State), and almost fifty articles about different constitutional and political issues.