As President, his moderate and cautious attitude towards the occupation of the Chincha Islands by a Spanish Fleet in 1864 was used as an excuse to launch a military uprising that drove him out of power.

When General José de San Martín with the Chilean army obliged the viceroy to evacuate Lima in 1821, young Pezet joined the patriots and took part in the campaign as sub-lieutenant.

He became captain in 1828, and in 1835, as colonel of the battalion of sharp-shooters of Rimac, he took part in the rising of President Agustín Gamarra against the Peru-Bolivian Confederacy and was banished.

In 1859, Pezet was secretary of war; in 1862, he was elected first vice-president with General San Román,[1] assuming the presidency following the death of the latter in 1863.

But when he signed a treaty with the Spaniards on 27 January 1865, which was considered derogatory to Peruvian national honor, a general uprising followed, so on November 7, 1865, he delivered the executive office to the vice-president and retired to Europe, settling in Richmond, England.