King Hans From Claus Berg's famous altar piece in Sct. Knud's Church, Odense, Denmark

In accordance with an old agreement, Hans was to be elected King of Denmark, Norway and Sweden upon the death of Christian I in 1481. At an assembly of the Estates of the Realm in May of 1482, he was elected King of Denmark. The following year the Norwegian Privy Council recognized him as King, and the coronation charter could thus be signed. Later that year the Swedish Privy Council followed suit, but Sten Sture, the Swedish Regent, managed to postpone the coronation. Sten Sture in fact ruled Sweden, but abstained from being crowned king in order not to openly violate King Hans' right to the throne.

Dorothea, the Queen Mother, was persistent in her efforts to have Frederik, her favorite son and Hans' younger brother by sixteen years, appointed Duke of Schleswig-Holstein. Hans was not prepared to give in immediately, and in 1490 an agreement was reached to divide the duchies in southern Jutland. In this way King Hans succeeded in preventing the duchies from becoming totally separated from the Danish crown. The younger brother, the later Frederik 1., was allowed to choose first, and he chose the Gottorp part.

To avoid breaking an agreement to keep the duchies undivided, Hans and Frederik were supposed to rule them together. In the following years, when Dorothea and Frederik demanded that Norway and Sweden be divided in a similar way as the duchies, King Hans, however, remained steadfast. During the third Danish assembly of the Estates of the Realm in Kalundborg in 1494 the kingdom was declared indivisible.

In 1497 King Hans marched towards Kalmar, Sweden with an army of 10-15,000 men. From there he sailed with a fleet to Stäket north of Stockholm, which was being besieged by Sten Sture. Sten Sture had to abandon the siege and fled to Stockholm, while a peasant army advanced to his rescue. Sten Sture and the peasant army were defeated in two large battles, and in November the coronation of Hans took place in Stockholm.

When King Hans returned to Denmark, he and Frederik agreed to subjugate the old peasant republic of the Ditmarshes. Duke Frederik and King Hans attacked the Ditmarshes with a joint army of 12-15,000 men, and the result of this attack was disastrous. On that day, the weather turned into sleet and rain, and on the narrow, muddy road on the dikes with deep ditches on both sides, the heavy cavalry and the German mercenaries were doomed. The king and the duke escaped, but they had suffered a humiliating and ignominious defeat.

The defeat in the Ditmarshes encouraged the Swedes to secede from Denmark, and on August 9, 1501 King Hans received a letter of secession from the Swedish lords. Queen Christine was imprisoned at Stockholm Castle, where she – aided by about 1000 men – defended herself against the Swedish assault on the castle. After a siege of about seven months, the queen and the remaining 70 men left the castle on the promise that they be allowed to return to Denmark. Three days later King Hans and the seneschal Poul Laxmand arrived in the Stockholm Archipelago with a large fleet. Since the Danish flag no longer flew over Stockholm Castle and the Swedes – as King Hans later claimed – threatened to mistreat Queen Christine, Hans had to return to Denmark. Despite promises by the Swedes, Queen Christine was kept imprisoned and not released until 1503.

King Hans never succeeded in reconquering Sweden, and in the ensuing years he was marked by bitterness and a sombre disposition. As a result of the war against Lübeck during the later years of his reign, Hans established Denmark's first royal navy. During his reign the Norwegian-Danish navy achieved its first victories over the Lübeckers, and in 1512 Lübeck and the other cities in the Hanseatic League were pressured into an agreement that affirmed their trading privileges in the Nordic countries, though Lübeck in exchange had to recognize the right of the merchants from the Netherlands to sail in Danish waters.

King Hans died in Aalborg in 1513 shortly after a fall with his horse in Skjern creek. 32-year-old Christian, the successor to the throne, was now ready to continue his father's line, only at an even greater speed.

King Hans lies buried in St. Knud's Church in Odense.