Guillermo was born and raised in Miami, Florida, in an Ecuadorian-Nicaraguan family. He graduated from Johns Hopkins University with a bachelor's degree in international studies. Since then, his career has centered on governmental budget response to the needs of society and offers public opportunities to shape it. At the Center on Budget and Policy Priorities, he advocated for U.S. fiscal policies that benefit low-income communities and against those that would exclude or harm them, such as the 2017 Tax Cut and Jobs Act. Later, at the International Budget Partnership, he collaborated with civil society, government, and international organizations to advance open and accountable budgets, like in the 2019 U.N. SDG Action Zone. He completed his MPA internship with the United Nations this summer. In his free time, Guillermo enjoys cooking, hiking, and spending time with his wife and cat.