Of converso origin, Fernández de Palencia was educated at the palace of the bishop of Burgos, Paul of Burgos, a former rabbi who had been converted to Christianity by Saint Vincent Ferrer. Fernández de Palencia became acquainted with Paul of Burgos’ son, Alfonso de Cartagena.
Fernández de Palencia went to Italy where he entered the service of Cardinal Bessarion, with whom he remained in Florence until 1453. He became acquainted there with Vespasiano da Bisticci, and studied the humanities with George of Trebizond at Rome.
When he returned to Spain, Fernández de Palencia stayed for a time at the home of the Archbishop of Seville, Alonso I de Fonseca. Fernández de Palencia succeeded Juan de Mena as royal chronicler and secretary to Henry IV of Castile. In 1468, he became a supporter of Prince Alfonso (who proclaimed himself "Alfonso XII") and intervened in the negotiations for the matrimony between Ferdinand and Isabella, which occurred in 1469. On Isabella’s accession to the throne in 1475, Fernández de Palencia lost his post as royal chronicler.
During the War of the Castilian Succession, he served as a diplomat for Castile, assisting in the establishment of the Santa Hermandad in 1476 and the organization of naval reinforcements for the defense of Gran Canaria, a Castilian possession, in 1479. According to Fernández de Palencia, he lost favor with the queen in 1480.
He died in 1492.
Chronicles (Décadas) 
His main work is the Gesta Hispaniensia ex annalibus suorum diebus colligentis, called, for short, his Décadas, because it was divided into decades in the style of Livy's work. This chronicle, written in Latin, covers the time from the end of the reign of John II of Castile to the year 1481, including the reign of Henry IV of Castile; Henry IV’s war with Prince Alfonso; the War of the Castilian Succession; the consolidation of Castile and Aragon under Ferdinand and Isabella; and the signing of the Treaty of Alcáçovas.
The work is divided into four decades, each one consisting of 10 books except the fourth, which was left incomplete at Fernández de Palencia’s death, and consists of 6 books. The first three decades were translated into Spanish by Paz y Meliá and published under the title of Crónica de Enrique IV between 1904 y 1908. Most historians remained unaware of the fourth decade, which was published in 1971 by José López del Toro.
The other important work by Fernández de Palencia is his Anales de la Guerra de Granada, which concerns the Granada War from its beginnings until the taking of Baza in 1489. It was translated into Spanish by Paz y Meliá in 1909.
Fernández de Palencia also wrote Batalla campal entre los perros y los lobos (Pitched Battle Between the Dogs and the Wolves) (1457, which is a Castilian translation of his own Latin poem. It may be an allegory for the government of Henry IV of Castile. A wolf, Harpaleo, is killed by dogs after he is weakened by his neglect of military discipline. Fernández de Palencia also translated into Castilian his Latin work, the allegory Tratado de la perfección del triunfo militar (1459. A character named “Exercise” (el Ejercicio), accompanied by the wise Discretion (Discreción), tries to find the character named Triumph (el Triunfo). Triumph refers Exercise to a Roman captain named Gloridoneo, who may represent Alfonso V of Aragon. Gloridoneo is victorious in battle and Triumph grants victory to Order, Exercise, and Obedience –virtues which will help a king emerge victorious, advice that may have been directed to Henry IV.
The work Coplas del provincial (The Provincial’s Couplets) is attributed to him.
He also wrote lexicographical and linguistic works:
- Opus Synonymorum, also known as De sinonymis elegantibus–, which concerns synonyms
- Uniuersale Compendium Vocabulorum (Vocabulario universal en latín y en romance) (Seville, 1490), bilingual Latin-Castilian dictionary, subsequently superseded by the work of Antonio de Nebrija.
- Compendiolum, a geographic and toponymic work
- Latin epistles
- López del Toro, José, Cuarta Década de Alonso de Palencia (Madrid: Real Academia de la Historia) 1971 ISBN 84-600-6271-6
- Universal vocabulario en latín y en romance Madrid: Comisión Permanente de la Asociación de Academias de la Lengua Española, 1967, 2 vols.
- Gesta... Década IV, libro 36, cap. 1