Born into a middle-class family, Portales amassed a small fortune early in life. In 1824 he was awarded a monopoly on tobacco, tea, and liquors that proved immensely profitable but aroused the anger of the Chilean landowners. Upon termination of the monopoly after a few years, Portales founded two newspapers to expound his authoritarian doctrines. When the Conservative Party entered office in 1830, he was, as chief minister, the real power in the land. Disdainful of political freedoms, he imprisoned his pipiolo (liberal) opponents, silenced the opposition press, and subdued the army. Portales ruled through the constitution of 1833, a document that created a centralized state dominated by the conservative oligarchy. Liberals and military leaders were barred from participation in the government.

Disturbed by increasing trade competition from Lima and the threat of a combined Peru-Bolivia confederation, Portales initiated war with the Peru-Bolivia alliance in 1836. This trade-inspired war was ultimately won by Chile, but Portales was assassinated by rebellious militaries while reviewing his troops. Nonetheless, he had set Chile on a path of political stability and economic progress.