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, Hierrro López served as National Representative, Senator and as Ministry of the Interior. He also served as President of the Chamber of Representatives the fifth session of the 42nd Legislature. In November 2020, he was approved by the Senate as Ambassador of Uruguay to the Republic of Peru.