Isaac Herzog has been elected new chairman of Israel's Labour Party with 58 per cent of the votes.
Mr Herzog replaces Shelly Yachimovich as the leader of the largest opposition party in the country.
Mrs Yachimovich has led the party since 2011.
He said: "We are embarking today on the real journey to change the face of the state."
Fifty-two per cent of eligible voters took part in the balloting on Thursday in Tel Aviv.
Despite losing, Mrs Yachimovich called Mr Herzog to congratulate him on his victory.
Mr Herzog remains keen to work with the former leader, and sees her as an “important partner” in leading the party back to power.