Hernández founded the newspaper El Río de la Plata, which advocated local autonomy, abolition of the conscripted "frontier contingents", and election of justices of the peace, military commanders, and school boards.

He envisioned a federal republic based in pastoralism, but also featuring a strong system of education and a literate population.

Although a federalist opposed to the centralizing, modernizing, and Europeanizing tendencies of Argentine president Domingo Sarmiento, Hernández was no apologist for General Juan Manuel de Rosas, whom he characterized as a tyrant and a despot.

Hernández is known today almost exclusively for his masterpiece Martín Fierro, the epic poem that stands as the pinnacle of gauchesque literature.

Hernández died of heart disease on 21 October 1886, in Belgrano, which was at that time a separate suburb, and is currently a neighborhood of the city of Buenos Aires.