King Władysław Jagiełło took advantage of its specific location, and chose it for the place for court sessions and meetings of noblemen.

In 1331, before the expedition to Płowce, the king appointed his son Casimir as the steward of Wielkopolska. After the death of Łokietek, Casimir the Great extended the castle, making it one of the most powerful fortresses on Polish soil. Castle Chęciny took over the role of administrative centre from Małogoszcz and became the seat of starostes and capital of the poviat. Throughout its history, the castle served different functions. As the residence of Queens, it hosted the second wife of Casimir the Great, Hessian princess Adelaide, Elizabeth Łokietek, exercising governance for her minor son Ludwik, Sophia, wife of King Władysław Jagiełło, and Queen Bona, who stopped here during her trip to Bari).
The castle was also used as a state prison – Andrzej, brother of Władysław Jagiełło was imprisoned here, as well as the leader of the Teutonic Knights, Michael Kuchmeister von Sternberg and other Teutonic masters.
After capturing Małopolska, Łokietek moved the crown treasury to Castle Chęciny, and in 1318 also moved the treasury of the archdiocese cathedral in Gniezno. Finally, the castle was assigned for living quarters of starostes, and a place of the court and city law. It was home for vice-starostes, city writer, judge, margrave, steward, cook, gatekeeper and chaplain. In the oldest part between two cylindrical towers there was a courtyard with an apartment building. There was a chapel of Ten Thousand Martyr Soldiers adjacent to the castle. In 1576, the court was encased with galleries, the tower was extended with brick and the castle was extended with a large courtyard with a rectangular tower. A 100-metre well was dug in the rock. In 1607, the castle was captured by deceit and burned down by Zebrzydowski troops. In 1657, the rebuilt castle was destroyed by the Rakoczy troops. It was destroyed again in 1707 during the wars against the Swedes. From that moment it did not return to glory, remaining in partial ruins. Its cannons fired for the last time in 1787, when Stanisław August Poniatowski passed through Chęciny. After the partition, the castle came under the Austrian rule and fell into increasing disrepair.