The siege, was carried out from 1245 through 28 February 1246 by forces of the Crown of Castile and the Order of Santiago commanded by Ferdinand III of Castile and the Grand Master of the Order of Santiago, Pelayo Pérez Correa, against a combined defending force of the local Taifa of Jaén (جيان) and the Emirate of Granada under Muhammad I.

He was supported in this new campaign by Pelayo Pérez Correa, the Grand Master of the Order of Santiago.

At the start of the siege, the Castilian forces began launching attacks on the various city gates, all of which were ineffective in terms of capturing any points on the main wall, however they did in many instances manage to drive the defenders off the bulwarks of the outer defenses.

A force led by Don Alvar Gil de Villalobos was obliged to give chase in an attempt to rescue their captured supply train; however the Moorish knights fled, leading the Castilian rescue party into an ambush by some 50 more knights and around 100 infantry soldiers.

On 28 February 1246, in an attempt to consolidate power over his dominions, Muhammad I, King of Granada, ordered the surrender of Jaén to Castilian forces in accordance with his signing of the Treaty of Jaén which effectively turned the Emirate of Granada into a vassal state of the Crown of Castile.