On paper it is the hereditary monarch, but they have no real power, so de facto it is the prime minister. Their role is to lead and to appoint ministers in the government, which is considered Sweden’s leading body.
The prime minister is selected by the parliament, the representation of the Swedish public, which is also responsible for deciding on laws and holding them and the government in check overall.
The prime minister has no term limit but they tend to lose support from the parliament (which gets elected every four years) sooner or later. For instance, the last prime minister, Magdalena Andersson, stayed less than a year.
Edit: fixed typo
So why maintain the hereditary monarchy, even in a limited capacity? What role does it serve?
Good question. Since 1974, the monarch’s role has been reduced to a purely ceremonial one because of common sense, but then and still today a lot of people think they’re valuable for our shared identity as a people. However, an ever-growing amount of Swedes such as me whole-heartedly disagree and advocate republicanism.
One fine day, when the monarchy has been relegated to the annals of history, where will Swedes turn to find their national identity, assuming a national identity is worthwhile?