New Scottish Labour leader Richard Leonard promised to offer voters a "message of real hope" as he set his sights on becoming the country's next first minister.
The former trade union organiser who was elected to Holyrood 18 months ago defeated the more moderate MSP Anas Sarwar as Scottish Labour elected its fourth leader in just three years.
While his predecessor Kezia Dugdale had campaigned against Jeremy Corbyn, the election of Mr Leonard will be seen as moving the party more to the left.
Under Mr Corbyn Labour has enjoyed a surge in support, with the UK leader saying the result of the latest leadership contest could be a "turning point in Scottish politics"
Mr Leonard's election was however, overshadowed by the news Ms Dugdale is take part in the reality TV show I'm A Celebrity...Get Me Out Of Here!.
The Labour group at Holyrood will now consider if she should be suspended in the coming days, Mr Leonard confirmed, although he stressed this course of action was not his "immediate response" to the news.
With Labour now the third party in Scottish politics behind the SNP and the Conservatives, Mr Corbyn accepted there is "much to do to continue our party's revival in Scotland".
But he said: "Richard's campaign offered a challenge to the rigged system that has benefited a wealthy elite and showed how he will lead Scottish Labour to transform society.
"This can be a turning point in Scottish politics and our party will now come together, united to challenge Tory and SNP austerity that has held Scotland back.
"I am confident that under Richard's leadership, Labour will once again be a real force for change in Scotland.
"I look forward to campaigning with him in Scotland next week as we build a movement that will help our party win in Holyrood and Westminster, to transform our country for the many not the few."
After a leadership contest which was at times bitter and divisive, Mr Leonard was the choice of 12,469 party members and supporters - 56.7% of those who took part in the ballot
And he said his victory showed said the party was "hungry for a Scottish Labour leadership guided by principle, driven by passion, rooted in experience".
Speaking to activists at the Glasgow Science Centre after the result was announced, he pledged Labour would be the "radical party of change once more".
Mr Leonard said: "We have started to build a Scottish Labour Party which people can believe in again, we are only at the beginning.
"After this leadership election we will reunite on the basis of our values, values forged in the fire of daily struggles, reconnecting with people in workplaces and in communities right across Scotland."
He added Labour must now "take to the people of Scotland a new message of change, a message of real change, and so a message or real hope".
And while he said Scotland had endured a "lost decade of nationalist mediocrity" under the SNP, his party could win the battle of ideas with the nationalists.
Mr Leonard said: "Our shared purpose is clear, to build again, to win again. Our purpose today is not just electing a leader, my aim is to be the next Labour first minister."
Scottish Conservative leader Ruth Davidson congratulated Mr Leonard, but said: "As Labour's ninth leader since devolution, many people will be wondering whether he will turn out to be another temporary solution to his party's deep seated problems."
She added: "Scottish Labour has spent far too long fighting itself in an endless succession of leadership contests, instead of fighting for a better deal for the people of Scotland.
"The Scottish Conservatives are the only party with the strength and unity to stand up to the SNP and provide the strong opposition our country needs."
Meanwhile SNP business convener Derek Mackay commented: "In recent years, few revolving doors in Scotland have revolved as much as that of the Scottish Labour leader's office.
"Mr Leonard has, perhaps, an impossible job on his hands in trying to weld together the warring factions of a deeply damaged and divided party - not least amongst his many parliamentary colleagues who did not support him.
"Meanwhile, the SNP will continue to focus on delivering progressive government, supporting our public services and standing up for Scotland's jobs and economy in the Brexit negotiations."
Mr Leonard takes over the top job at a time when politics has been rocked by allegations of sleaze and sexual misconduct, with Alex Rowley having recently stepped down as Scottish Labour deputy leader after a former partner complained about his conduct in their relationship.
The new leader immediately pledged there would be "zero tolerance" of sexism, misogyny and sexual harassment.
"We need to change the political culture," Mr Leonard declared, as he vowed to set up an independent route for complaints of this nature.
He made clear that he believes politics is not about personalities, and should instead be "about the principles and politics and the values that you have got".
And he insisted: "I think there is a renewed appetite for a Labour Party which is offering a message of hope. There is a growing interest in some of these traditional Labour ideas around extending public ownership, around a redistribution of not just wealth but power and certainly there is widespread support for an end to the politics of austerity.
"These are the kind of radical ideas that are distinctive Labour ideas on which I stood in this election, through which I have received a mandate from the Scottish Labour Party members.
"There is already evidence I have seen of people who are coming across to that message who are not just former SNP voters but former SNP members. There are people coming across to that message who maybe voted Yes in the 2014 referendum, who are attracted by a message of change, a message of hope and that we can't go on as we are.
"But it is also about rekindling belief in those diehard Labour voters who have stuck with us. That creates the potential for a real movement for change and that is what I want to build."
While the party may have been divided during the leadership contest, Mr Leonard said: "The Labour Party in my view will come together, because we've got no choice. We are in third place, we don't have the luxury of continuing splits and divisions.