He was in Guatemala when the United Provinces of Central America approved inclusion into the First Mexican Empire of Agustín de Iturbide.

He was a deputy to the state congress in 1826, 1827 and 1828, when El Salvador was part of the Federal Republic of Central America.

Together with Manuel José Arce Cornejo proclaimed the separation of El Salvador from the Union in 1832.

On 17 March of that year the Salvadoran town of Chalatenango pronounced against Cornejo and in favor of the federal government.

Cornejo was locked up in the San Francisco convent in Guatemala and never returned to politics.