The Labor Party on Sunday chose Merav Michaeli, a veteran lawmaker and former journalist, as its new leader ahead of the March elections.
Michaeli, who took 77% of the votes in the primary, faces a difficult task as she tries to revive the fortunes of the iconic party.
Labor guided Israel to independence in 1948 and led the country for its first three decades. But it has struggled to remain relevant over the past two decades as peacemaking with the Palestinians ground to a halt and the electorate appears to have embraced Prime Minister Benjamin Netanyahu's hard-line ideology.
Opinion polls have forecast Labor will not receive the minimum four seats, or 3.25% of the votes, needed to enter the next parliament.
Michaeli has been a leading progressive voice in Knesset, supporting women's rights, LGBT causes and the rights of workers in addition to seeking a resume of peace talks with the Palestinians.
Michaeli also broke with fellow Labor MKs Amir Peretz and Itzik Shmuli when they decided to join the coalition government Netanyahu and Blue & White chairman Benny Gantz formed following the March 2020 election, serving as an independent lawmaker in the opposition.
In a message to supporters posted on Facebook, Michaeli urged people to "come home."
"I call on people who feel that politics doesn't represent them, to those who feel that politics doesn't hear their voice, come home," she said.
"Even if the Labor Party wasn't your home in the past, I promise to represent all of you."