Born into a political family, his father was Luis Hierro Gambardella, former Minister of Education and Culture and Parliamentarian, while his grandfather, Luis Hierro Rivera, was National Representative. Member of the Colorado Party, Hierro López served as National Representative, Senator and as Ministry of the Interior.
Hierro López's background in politics was shaped by his family ties, with his father Luis Hierro Gambardella holding positions such as Minister of Education and Culture and Parliamentarian. His grandfather, Luis Hierro Rivera, had also held public office as a National Representative. As a member of the Colorado Party, Hierro López pursued a career in politics, serving in various roles including National Representative, Senator, and Ministry of the Interior.