The final verdict is to be announced by a party congress in Berlin on February 26, which will also vote on the "loveless" coalition deal with the Social Democratic Party (SPD), which has caused criticism of Angela Merkel for giving up key ministries in the government to counterparts from the SPD.
The hard-fought coalition deal struck with Social Democrats must still be approved by the SPD's 460,000 members.
He stepped down as SPD chief last week, just days after he clinched the coalition agreement with Merkel that has divided the centre-left party. She had to make painful concessions to the SPD to break months of political deadlock after an inconclusive election on September 24.
Accepting the nomination, Ms Kramp-Karrenbauer promised an overhaul of the party's policies. "My impression is that here too. we can achieve something by making good arguments".
In another sign of the increased pressure the established parties are facing, the far-right Alternative for Germany (AfD) surpassed the center-left Social Democrats (SPD) for the first time in a national poll to become the second-strongest party, an Insa survey for the daily Bild showed.
In what was called its worst post-war performance, the SPD received just 20.5 percent of the vote in the recent parliamentary elections in September 2017.
Expect the SPD vote to go down to the wire.
Uber's net loss widens to $6.1 billion after a troubled 2017
Last Friday, Uber settled a lawsuit brought by Google , which accused it of stealing its technology and infringing its patents. Uber's loss was mainly based on accepted accounting standards, which includes write-downs and significant legal expenses.
German Chancellor Angela Merkel put forward on Monday her close ally Annegret Kramp-Karrenbauer, premier of the tiny western state of Saarland, to take over as secretary general of her Christian Democratic Union (CDU), party sources said.
"The promise to renew the party seems to work", he added.
Merkel herself has been badly weakened by her lengthy struggles to form a new government and media are openly speculating that she may not complete a full fourth term as chancellor even if the SPD rank-and-file give the thumbs up.
The decision to entrust Kramp-Karrenbauer, also known by her acronym AKK, with bolstering the CDU after it lost ground in an election past year, is significant as some party members are starting to look ahead to a post-Merkel era.
She has been on the short list of party grandees considered to eventually replace Dr Merkel.
Kramp-Karrenbauer, a close ally of the chancellor, is now minister-president of the southwestern state of Saarland and a member of the CDU's executive committee.
"We are experiencing one of the most hard political phases in the history of (post-war) Germany", Kramp-Karrenbauer told reporters, explaining why she was willing to leave her post as governor of one of Germany's 16 states to devote her energy to the party's headquarters in Berlin.