His political roots were in the Department of Treinta y Tres, in the interior of the country.
His son Luis Hierro Gambardella became a Minister, Deputy and Senator.
His grandson Luis Antonio Hierro López became Vice President of Uruguay in 2000.
Hierro served as a Deputy for the Department of Treinta y Tres from 1920 to 1923.
This constituency was in 1955 to elect his son Luis Hierro Gambardella to the same office.