Kramp-Karrenbauer beat her closes rival Friedrich Merz in the second round of a party vote held on Friday, having defeated Jens Spahn in the first round.
The 56-year-old’s victory in the election propels her to becoming a favourite to take over as Germany’s next chancellor, though she may have to wait a few more years. Current chancellor Angela Merkel has in the past said she intends to remain in office until 2021.
Merkel delivered her last speech as party leader on Friday, drawing rounds of applause from party members.
Kramp-Karrenbauer is seen as a close ally of Merkel, and her rise to the conservative’s leadership is likely to solidify the latter’s legacy.
Until recently, Merkel had been widely expected to seek another term as party leader, but a series of disappointing election results seemed to change that. She announced in October that she will not seek re-election.