Fruto grew up in Guatemala and attended school there.
His father returned to Nicaragua after completing his studies and married Josefa Margarita Alfaro Monterroso in 1814.
They had six children, but Fruto was subsequently considered a member of this family, based on strategic needs related to administration of the family resources, for which the administrator was expected to be at least 25 years of age.
His half brothers and sisters, Pedro JoaquĂn, Dionisio, Carmen, Mercedes and Fernando grew under his guardianship.
Fruto's father was one of the founders of the Conservative Party of Nicaragua, centered on the city of Granada.
He was committed to the Conservative cause and became an activist of the Party.
In 1836, he became a representative in the State Assembly.
From 1839 to 1842, he was a Senator of the State of Nicaragua.
In 1842, an attempt was made to reestablish a union of Central American states as the Central American Confederation, in accord with the "Pact of Chinandega".
It was to include El Salvador, Guatemala, Honduras, and Nicaragua.
In 1843, Fruto Chamorro was appointed Supreme Director of the Confederation junta, and he took up residence in San Miguel, El Salvador.
However, Guatemala withdrew, and Fruto was instrumental in preventing a war over the decision.
The nascent Confederation collapsed in 1844.
In 1845, Fruto Chamorro was appointed Prefect and Military Governor of the Department of Granada, and Minister of the Treasury.
In November 1851, during the administration of Supreme Director Laureano Pineda, he became Commander-in-chief of the Army.
Fruto Chamorro himself became Supreme Director of Nicaragua on 1 April 1853.
Almost immediately and with support of the conservative oligarchy, he transferred the government headquarters to Granada, the Conservative stronghold.
He then convened a Constituent Assembly on 20 January 1854, to promulgate a new Constitution during the absence of the majority of the western (Liberal Party) representatives, virtually expelled from the country by the government's move to Granada.
In March, Fruto Chamorro relinquished his title as Supreme Director and with acquiescence of the Assembly, named himself President of Nicaragua.
The Liberals saw this as a restoration to power of the provincial oligarchy, continuation of a feudal economic system, and the diminished possibility of an alliance of all Central American reactionary forces as well.
They initiated a civil war by establishing their own government in LeĂłn in May 1854, with the support of the governments of Honduras and El Salvador.
A force under the command of General Máximo Jerez was sent to besiege Granada.
His defenses for Granada were successful and subsequent attacks failed to take the city.
A victim of dysentery, Fruto Chamorro died at his hacienda outside Granada on 12 March 1855.