Sandra León graduated from the Pompeu Fabra University (Barcelona) with a BA in Politics (1999) before going on to complete an MA in Social Sciences from the Juan March Institute (Madrid, 2002). Funded by 'La Caixa Foundation', between 2003 and 2005 she visited as a PhD student the Department of Government at Harvard University (MA, USA). In June 2006 she defended her Ph.D. thesis on The Political Economy of Fiscal Decentralization at the Universidad Autónoma de Madrid. Her thesis was supervised by José María Maravall at the Juan March Institute.
Her doctoral research explored the political motivations of politicians in designing intergovernmental transfers, bridging two different disciplines (public finance and political science) and integrating the analysis of economic and political factors. She won two prizes; both awarded to best PhD dissertations each year and her thesis was published as a book in 2007.
Between 2006 and 2011 Sandra worked as a researcher in different Spanish institutions - Escola Galega de Administración Pública (2006-2008) and Centro de Estudios Políticos y Constitutionales (2008-2011). She has taught various aspects of Comparative Government, ranging from and introduction to politics and political democratic theory, to advanced courses on political institutions, both at George Washington University (Madrid Study Centre) and at the Universidad Complutense de Madrid (2011-2012). In March 2013 she joined the Politics Department at the University of York.