He graduated with honours in Political Science with a specialization in International Relations at the University of Buenos Aires (UBA, 2003). He also holds a Master in International Relations (UBA, thesis in progress).
Guillermo has been a member of the network of global alliances CIVICUS since 2011. In 2014, he was elected to join AGNA (Affinity Group of National Associations) to represent Latin America. In 2016 he was elected to be a member of the Executive Directorate at CIVICUS. He is a promoter of the Civil Society Innovation Initiative (CSII) in partnership with the United States Agency for International Development (USAID) and the Swedish Agency for International Development (SIDA).