The war marked the last time Sweden participated in an armed conflict with another nation, and its conclusion signalled the beginning of the country's long period of military neutrality.

As early as in 1812, prior to the Napoleonic invasion of Russia, the Swedish Crown Prince Charles John (Karl Johan) – formerly Marshal of France Jean Baptiste Bernadotte – had entered into an agreement with Tsar Alexander I that Russia would support a Swedish attack on Norway in order to force Denmark–Norway to cede its northern part to Sweden.

By 14 December, Bernadotte agreed to an armistice and peace talks began in Kiel on the basis of ceding Norway to the Swedish king in return for Swedish Pomerania, additional territory in North Germany, specifics to be decided at the general peace conference following the cessation of hostilities between the Sixth Coalition and Imperial France, as well as 1,000,000 Riksdalers.

[7] Ultimately, Denmark would pay a catastrophic price for the treaty, as Karl Johan viewed this support, no matter how covert, as betrayal and a violation of the treaty, and this would later be reflected in the final peace settlement at the Congress of Vienna, which voided Kiel's promise to compensate Denmark for its loss of Norway with Swedish Pomerania, various additional Northern German territory, and 1,000,000 Riksdalers.

As the head of the new state, Christian Frederick desperately tried to gain support from the United Kingdom, or any of the other major powers within the Sixth Coalition, in order to maintain Norway's independence.

The main Swedish offensive came across the border at Halden, bypassing and surrounding the fortress of Fredriksten, and then continuing north, while a second force of 6,000 soldiers landed at Kråkerøy outside of Fredrikstad.

On 3 August, King Christian Frederick reached the front at Østfold and was persuaded to change his strategy and use the 6,000 men stationed at Rakkestad in a counterattack against the Swedes.

Every day of delay in securing Norway by the Swedes brought uncertainty to them regarding the outcome, so both parties were interested in a quick end to the war.

The proposal included a major concession – Charles XIV John, on behalf of the Swedish government as regent for his ill adopted father, accepted the Eidsvoll constitution.

Its constitution was upheld with only such amendments as were required to allow it to enter into the union, and the two united kingdoms retained separate institutions, except for the king and the foreign service and policy.