He participated in all the campaigns of the Patria Vieja (1811–1814), and after the defeat of Rancagua, he was left stranded between the Royalist armies.
Captured by the Spanish authorities, he was exiled to the Juan Fernández Islands, where he remained imprisoned until after the victory of Maipu.
In 1824, Muñoz was elected a deputy for "San Carlos" (1824–1825), and in 1826 was reelected, this time for "Santiago" (1826–1827), being vice president of the chamber from January 8 to February 5, 1827.
During that period, President Francisco Ramón Vicuña appointed him as Secretary of War and Navy.
Muñoz fought in the Chilean Civil War of 1829, and after the final defeat of the Liberals at the Battle of Lircay, he was exiled to the town of Huasco in 1833, where he died at the age of 56.