Mariano Castillo is an American journalist and writer based in Atlanta, Georgia. He is a writer and weekend supervising editor for CNN Digital, alternating roles that see him covering national and international news or overseeing the day's assignments.  
Castillo graduated from Texas A & M University with a Bachelor's degree in journalism and international studies. He went on to attend Columbia University School of International and Public Affairs, where he received a master's degree in international affairs.  
Castillo joined CNN in 2009 as a digital journalist embedded with CNN en Español CNN, leveraging that network's resources in Latin America to produce reporting to be used by CNN's English-language networks.  
Foreign Policy magazine has twice included Castillo in its annual "Twitterati 100", a list of top people to follow on global affairs. He is also part of the community of Soros Fellows.