By this time, Vigo was experiencing a considerable transformation and expansion as a port city and commercial center, but the poor living conditions in Galicia still required workers to emigrate.

During this time, he began his journalistic career working with the bi-weekly newspaper La Verdad, a representative of republicanism, and supporter of the claims of the Galician proletariat, denouncing the exploitation of workers in Galicia.

The sharp and controversial nature of his writings brought him into conflict with the Marquis José Elduayen, a canovista politician and local representative of the central conservative power under Prime Minister Práxedes Mateo Sagasta.

In April 1881, Mella was sentenced by the Provincial Court to 4 years and 3 months of exile and a fine of 625 pesetas.

In 1881 Mella founded La Propaganda in Vigo, a federalist publication with a focus on labor issues that lasted until 1885.

In 1884, he collaborated with the monthly publication Acracia and the Barcelona Newspaper El Productor to translate Bakunin's God and State into Spanish.

Some of his writings received international awards and were translated into Italian, Dutch, Portuguese, English, and French.