Kronborg began as Krogen, a fortress built by King Erik of Pomerania in the 1420s at the narrow entrance to the Øresund. From this position Denmark could enforce the Sound Dues, levied from ships passing between the North Sea and the Baltic from 1429. The toll became an important source of royal revenue and made control of Helsingør strategically significant. Krogen combined defenses with rooms for the king and officials, but the growing wealth and ceremony of the Danish monarchy eventually demanded a more imposing setting.

Frederick II transformed Krogen between 1574 and 1585 into the Renaissance palace renamed Kronborg. Architects including Hans van Paeschen and Anthonis van Obbergen created a four-wing complex with towers, copper roofs, royal apartments, a chapel, and a great ballroom. Rich stonework and interiors proclaimed dominion over the gateway to the Baltic. Gunners, customs officers, sailors, servants, craftsmen, diplomats, and courtiers made the castle part fortress, part toll station, and part royal residence.

A fire in 1629 destroyed much of the interior, though the chapel survived. Christian IV rebuilt the palace, restoring its profile and renewing decorated rooms. War soon brought a more serious loss. Swedish forces besieged and captured Kronborg in 1658 during the Dano-Swedish conflicts, carrying away furnishings, art, and equipment before Denmark recovered the site. New outer defenses strengthened the landward approach, but the royal family used the palace less often as military needs came to dominate.

From the eighteenth century Kronborg functioned mainly as a fortress and garrison; part of it also served as a prison. Soldiers occupied buildings once designed for court display, and prisoners performed labor within the fortifications. Shakespeare's Hamlet, written around 1600 and set at “Elsinore,” gradually gave Kronborg an international literary identity even though the play does not document events at the castle. The Sound Dues ended in 1857, removing the fiscal system that had originally justified the fortress's commanding position.

Military use continued into the twentieth century, after which restoration increasingly presented the Renaissance palace and its later defenses as a national monument. Performances of Hamlet reinforced the connection between the real fortress and the imagined court of the play. UNESCO inscribed Kronborg on the World Heritage List in 2000 for its role in northern European history and Renaissance architecture. Conservation now interprets toll collection, monarchy, war, garrison life, imprisonment, and theater together. Kronborg's cultural fame rests on fiction, but its historical importance grew from control of one of Europe's most consequential shipping passages.