The beginnings of the city reach back to the first half of the 15th century. In 1415 Wierzbieta Krotoski (or Krotoszynski), a knight of Wielkopolski origin from the Lodzi family, by the power of the privilege of Wladyslawa Jagielly took up residence in Krotoszyn at the site where today's city center is located. During the 16th century Krotoszyn passed into the hands of the Rozdrazewski family. It was destroyed during the period of the wars with Sweden but regained its splendor at the end of the 17th century. This splendor is exemplified 0by the town hall which was completed around 1689.

The next owners enriched Krotoszyn with new architechtural features. The last owners were members of the German princely family from Thurn and Taxis.
After World War I and the Wielkopolska Uprising, Krotoszyn found itself within the borders of the reborn Poland. In September 1939 the town came under Nazi occupation.
Within the district there was underground and sabotage activity. The city was liberated on January 23, 1945.