Labour's only MP in Scotland, Ian Murray, has been appointed the party's shadow Scottish secretary.
The Edinburgh South MP previously quit the same post in 2016, in protest over the leadership of Jeremy Corbyn.
However, he has now been reinstalled by Mr Corbyn's successor, Keir Starmer, in a reshuffle which has also seen Ed Miliband returned to the front bench.
Mr Murray said Mr Starmer "understands that Labour's road back to power runs directly through Scotland".
Labour were reduced to one seat north of the border in December's snap general election - a low matched only by the 2015 election result, which again saw Mr Murray the party's sole Scottish representative.
'Huge rebuilding task'
The MP - who ran for the position of deputy leader, but was defeated by Angela Rayner - said the party has a "huge rebuilding task" having "lost the trust of voters".
He added: "By remaining true to our values of solidarity and internationalism, we will be clear on our constitutional position: opposing the SNP's divisive nationalism and an unwanted second independence referendum, forming a constitutional convention to bring power closer to the people, and supporting the closest possible relationship with the EU.
"By listening to the people of Scotland and the UK we will become an effective alternative government that looks to the future, not the past."
Mr Starmer, meanwhile, said he wanted to unite Labour so that it could "stand up for the interests of the Scottish people".
He added: "The road back to connecting with the Scottish public will not be quick or easy, but it will be my priority.
"I am delighted that Ian is joining my frontbench team. His experience of winning in Scotland and his understanding of the constitution will be vital for our party's future, with Holyrood elections just over one year away."
SNP Westminster leader Ian Blackford said he did not envy the position Mr Starmer had inherited, saying: "Support for Labour has collapsed in Scotland.
"If they are ever to regain trust, they must stop ignoring Scotland's wishes and respect our democratic right to choose our own future."