The town of Nový Jičín was probably founded in the 1380s at the crossroads of trade routes from Poland and Silesia to Bohemia and Hungary. Its regular layout suggests that it was founded "on green turf" as the economic centre of the Starý Jičín estate. However, the oldest written mention of the town dates back to 1313, when the town was granted its first town privileges (toll) by King John of Luxembourg. At that time, the town and the Old Jičín manor belonged to the Lords of Kravaře. In 1373, the Lords of Kravaře gave Nové Jičín the right to die, allowed the annual market and gave the basis for the town's coat of arms - a coiled arrow held by the hand of an armed man. The town was in their possession until 1434. Between 1500 and 1558, the Lords of Žerotín became the owners of the town and the manor, who made their mark in the history of the town mainly by rebuilding the original Gothic fortress, built at the end of the 14th century, into a comfortable Renaissance residence. Thanks to the Žerotín family, the construction of a stone arcade and town houses in the square began, as the town was made of wood until the devastating fire in 1503. Nový Jičín grew rich with its renowned cloth production and in 1558, after the departure of the Žerotins, it was redeemed from serfdom and became a chamber town. In 1620, King Frederick the Great made the town a royal town. The Thirty Years' War brought unprecedented hardships to the inhabitants. A year later, a great battle took place near Nový Jičín, during which the town was captured by the Protestant army of Prince Jan Jiří Krnovský and 500 Neapolitan soldiers were slaughtered on the outskirts. The great Baroque fires of 1768 and 1773 severely affected the whole town, but soon Nový Jičín rose to its next form. The town became the seat of the regional court, the construction of the Imperial Road brought connections with the world and the development of industry and trade. In the middle of the 19th century, Jews returned to the town and large textile factories were established, thanks to which the town is still called "the town of hats".

There are several legends about the name of Nový Jičín. According to one of them, the town was named after Jitka, the brave daughter of the owner of the Old Jičín Castle, who fought a bear to save a small boy. A shepherd, her future husband, saved her from the furious wounded animal. Jitka had a chapel built on the spot where she was rescued. Her husband then built a hunting lodge next to it, dedicated to Jitka, i.e. Jitčin, later Jičín. Another theory derives the town's name from the Slavic word dik, a wild boar that was abundant in the area. Hence first Dičín, later Jičín.