He was born in Santiago; the son of Manuel Ruiz de Tagle y Jaraquemada and María del Rosario Portales Larraín.

In his youth and according to the social norms of the time, he also became a militia officer in the "Regimiento del Principe" (Prince's regiment).

The son of a royalist family, he was a tepid participant in the Chilean War of Independence, especially during the period of the first government juntas.

From 1812 to 1814, he served as senator and president of parliament, and in 1814, he became councilman and mayor of the municipality of Santiago and became the provincial governor on February 13, 1817.

Immediately after Ruiz-Tagle took over as president, the principal leaders of the liberal side (Manuel Borgoño, Francisco de la Lastra and Juan Gregorio de las Heras) were eliminated from the army rosters.