He went to become a Professor of Exact Sciences at the National Teachers' School in Buenos Aires and around 1930, founded La Vanguardia, soon among the leading Socialist dailies in Argentina.
Encouraged by his brother, local Communist Party head Rodolfo Ghioldi, he ran as a Socialist for a seat in the Buenos Aires City Council, and was elected in 1948.
Becoming one of the few prominent left-wing lawmakers during the era of populist leader Juan Perón, Ghioldi was harassed by the Peronist regime and La Vanguardia was shuttered.
Following Perón's violent 1955 overthrow, Gholdi was invited to take part in the influential Civilian Advisory Board called by junta leader General Eduardo Lonardi.
The Socialist Party's 1958 convention, however, could arrive on no agreement as to their degree of opposition to Peronism (which, despite its ban, remained a powerful political force, skillfully managed by their leader in exile).