He freed the Picunche (northern mapuches) from Inca rule and he put up tenacious resistance to the conquest of their territories by the Spanish Empire.

in 1533 it welcomed the first Spaniard to arrive in the central area of current Chilean territory, Gonzalo Calvo de Barrientos, who had abandoned the viceroyalty of Peru insulted by Francisco Pizarro, who had him flogged and plucked as punishment for theft.

In 1540, the Spaniards under the command of Pedro de Valdivia entered Picunche territory, Michimaloco goes out to meet him with his army and the battle of the Mapocho River takes place, which Michimalonco loses.

While Valdivia felt that its entrenchment was definitive in the region, Michimalonco thought that its previous defeat would be avenged with the expulsion of the Europeans.

The very poor conditions in which this work is carried out, in addition to the insatiable thirst for gold of the Spanish, generates severe discontent among the Mapuches.

With tireless tenacity, Trangolonco visited all his allies in the Aconcagua and Maipo valleys, managing to gather a total of 10,000 warriors.

Then he addressed the Mapuches of Cachapoal and informed them about the events, giving them vibrant speeches, through which he exhorted them to continue the work of liberation begun with the expulsion of the Inca troops from the country.

After fighting the Spaniards, dejected by the continuous setbacks his cause was experiencing, he left the country and, crossing the Andes, sought refuge in Cuyo, still in the power of the Diaguitas.

"[3] Valdivia gratefully reciprocated the gifts and good intentions of Michimalonco, willingly accepting his offer as long as the Picunche people did not oppose the evangelizing action of the missionaries, submitting to the encomienda regime and contribute with labor to the exploitation of gold mines and placers.