Ph. D. in Economics at Sussex University, specializing in international economy. He holds a Master's in Public Administration (MPA) from the Program in Economic Policy Management (PEPM) at Columbia University. He also received a Bachelor's in International Relations from the University of El Salvador (USAL). He was a senior economist and Director of the Public Finances Department at Maxwell Stamp PLC, a financial consulting firm for development based in London. He led the analysis of macroeconomic risk for emerging markets at the Stock Shares department of Morley Fund Management, a leading investment fund in the United Kingdom.

He has worked in areas such as international trade issues, regional integration, fiscal policy and the impact of commercial policy on poverty and employment at the National Ministry of Economy, the Inter-American Development Bank (IDB) and the World Bank. Additionally, he has advised companies and governments in Africa, Asia and Latin America.

Castro is the author of numerous publications on a variety of subjects, including economic relations between Latin America and China, the impact of regional integration on economics and welfare, social effects of international trade, public infrastructure and location of foreign direct investment, regional development banks and regionalism and the effects of monetary policy on stock markets in emerging markets. He frequently contributes to both national and international press on the topic of the international economy.