[1] Álvarez Castro was born on a hacienda near the city of San Miguel, El Salvador.
During the era of the Federal Republic of Central America under Francisco Morazán, he became a Minister of Foreign Relations.
In El Salvador, Álvarez Castro participated in the attempted overthrow of Francisco Malespín, after which he exiled himself in Nicaragua.
After Malespín's fall from power, Álvarez Castro returned to his country where he retired from public life.
His poetry is collected in anthologies like Guirnalda Salvadoreña (1884) by Román Mayorga Rivas and Galería poética centroamericana (1888) by Ramón Uriarte.