Norbert Walter-Borjans, co-leader of Germany's Social Democrats (SPD) which emerged narrow victors following the September elections, is standing down at the party conference in December.
A party spokeswoman confirmed the decision, after Walter-Borjans had earlier made his intentions known to the Dusseldorf-based Rheinische Post newspaper.
Walter-Borjans was elected to chair the party along with Saskia Esken following a drawn-out election process in 2019 when the traditional party of the German left was deep in the doldrums.
"For me, being chairman was from the outset not linked to a further career, but rather the aim of bringing the party back on course," Walter-Borjans, 69, told the Rheinische Post. "I've come so far with this mission, that I can now say: someone younger should now take over."
Esken paid tribute to her co-leader, pledging that the SPD would pursue the current coalition talks to a successful conclusion.
After lagging badly in the polls, the SPD took 25.7 per cent of the vote in the elections, narrowly beating outgoing Chancellor Angela Merkel's conservative bloc into second place on 24.1 per cent.
The SPD is currently leading coalition talks with two smaller parties, the Greens, who took 14.8 per cent, and the pro-business Free Democrats (FDP), who took 11.5 per cent.
