First mentions about Sędziszów Małopolski come from 1320s, when its parish church belonged to the deanery at Dębica. The village belonged to the Odrowąż family, and due to efforts of Jan Odrowąż, Sędziszów was incorporated as a town on February 28, 1483, by King Kazimierz Jagiellończyk. In 1512 Sędziszów received the rights to organize weekly markets (on Tuesdays), and in 1555, the town passed to the hands of the Tarnowski family. In the 1620s, it belonged to Mikołaj Spytko Ligęza, who built roads and strengthened river banks. In 1649 Sędziszów Małopolski belonged to the Lubomirski family, and the town suffered in the 1650s. First, there was a plague, which decimated the population (1652), then, during the deluge, Sędziszów was destroyed by the army of George II Rakoczi. In 1661, the town passed on to the Potocki family, as a dowry in a wedding of Feliks Kazimierz Potocki with Krystyna Lubomirska. The Potockis made several investments in Sędziszów Małopolski, building a town hall, a new parish church and a monastery.