New Scottish Labour leader Richard Leonard has said his election sends a "message of real change".
The left winger became the fourth person to hold the post in the last three years after defeating rival candidate Anas Sarwar.
Mr Leonard, who only became an MSP last year, was the choice of 12,469 party members and supporters, while 9,516 backed Mr Sarwar.
Labour Jeremy Corbyn congratulated Mr Leonard on being elected, and Mr Sarwar on his energetic campaign.
He said: "After being written off time and again, the general election showed that our party is capturing the mood both in Scotland and across the rest of the UK.
"There is much to do to continue our party's revival in Scotland and many who still need to be persuaded to put their trust in the Labour Party.
"But 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."