[1][2] The first king from the House of Holstein-Gottorp, Adolf Frederick was a weak monarch, installed as first in line to the throne following the parliamentary government's failure to reconquer the Baltic provinces in 1741–1743.

Aside from a few attempts, supported by pro-absolutist factions among the nobility, to reclaim the absolute monarchy held by previous monarchs, he remained a mere constitutional figurehead until his death.

The Hat administration ended during the 1765–1766 parliament, where the Cap opposition took over the government and enacted reforms towards greater economic liberalism, as well as a Freedom of Press Act.

The Freedom of Press Act is unique for the time for its curtailing of all censorship, retaining punitive measures only for libeling the monarch or the Church of Sweden.

Stimulated by his consort Louisa Ulrika of Prussia (sister of Frederick the Great), he tried to regain a portion of the attenuated prerogative through the Coup of 1756 to abolish the rule of the Riksdag of the Estates and reinstate absolute monarchy in Sweden.

On the second occasion during the December Crisis of 1768, under the guidance of his eldest son, Gustav, he succeeded in overthrowing the "Cap" (Swedish: Mössorna) senate, but was unable to make any use of his victory.

Popular stories about his death having resulted from a large meal (consisting of lobster, caviar, sauerkraut, kippers, and champagne as well as 14 helpings of his favourite dessert hetvägg of semla pastries and hot milk)[10][11] are considered propaganda by modern writers.