Stefan Lofven submitted his resignation as Swedish prime minister on Wednesday after seven years on the job, a move that has been expected for weeks.
Lofven's resignation puts Finance Minister Magdalena Andersson one step closer to becoming the Nordic country's first female prime minister.
She already replaced him last week as the leader of the centre-left Social Democrats.
Lofven, 64, had announced in August that he would first retire as party leader and then as head of government.
In doing so, he wanted to give Andersson, 54, the opportunity to better position herself before the next Swedish parliamentary election in the late summer of 2022.
Andersson, a trained economist from north of Stockholm, would become prime minister so long as a majority in parliament does not vote against her, but a victory is not a foregone conclusion.
First, parliament speaker Andreas Norlen must sound out who has the best chance of forming the next government.
A safe bet
Andersson is a safe bet for the choice, but if successful she then must be approved by lawmakers in a vote.
She will need lawmakers not only from the Social Democrats and the co-ruling Greens, but also the Left Party and the Centre Party. Those two parties have already begun to issue the terms of their support.
Lofven has led a fragile centre-left minority government with the Greens since elections in 2018. Major policy initiatives have been hampered by the Social Democrats' weak standing in parliament, with the past several months of his administration especially tumultuous.
Lofven will remain in office in a caretaker capacity until parliament approves his successor.