Angela Merkel was replaced on Saturday by Armin Laschet as chairman of Germany’s Christian Democrats (CDU).
Laschet, the premier of the western state of North Rhine-Westphalia won a runoff vote against Friedrich Merz.
He secured 521 votes against Merz’s 466, putting him on course to run as the party’s candidate for chancellor in federal elections in September.
Ballots were cast by 1,001 party delegates.
Merkel, Europe’s predominant politician and a consistent winner with German voters since taking office in 2005, has said she will not run for chancellor again.
“I want to do everything so that we can stick together through this year… and then make sure that the next chancellor in the federal elections will be from the (CDU/CSU) union,” Laschet said in his victory speech.
Laschet, 59, presents himself as the Merkel continuity candidate, and she said last year he had “the tools” to run for chancellor, the closest she has come to endorsing anyone.
By tradition, the CDU chairman is usually – though not always – the chancellor candidate for the CDU .
The party, with its Bavarian sister party, the Christian Social Union (CSU), and the conservative bloc is on course to win September’s federal ballot.
However, polls show Markus Soeder, the CSU leader, is the conservative most favoured by voters.
Some CDU lawmakers want dynamic Health Minister Jens Spahn to run for chancellor, though he has backed Laschet for the party leadership.