The Scottish Labour leader has insisted that he still has the backing of the party despite growing calls for him to quit.
Richard Leonard said the party’s best chance in next May’s Scottish Parliament election was for it to “unite behind me”.
Four Scottish Labour MSPs have openly called on Mr Leonard to resign.
Shadow cabinet minister Rachel Reeves has also now said he should “consider his position”.
In an interview with Sky News, Ms Reeves said opinion polls in Scotland were “dire” for Labour despite the party appearing to be neck-and-neck with the Conservatives across the UK as a whole.
The shadow Cabinet Secretary urged Mr Leonard to “consider his position and do what he thinks is right for Scotland and for Scottish Labour”.
A spokesman for UK Labour leader Keir Starmer said on Wednesday that the issue was one for Scottish Labour, and insisted that the two leaders had a “very good working relationship”.
Mr Leonard said Ms Reeves was not a member of Scottish Labour.
He told BBC Radio’s Good Morning Scotland: “I am elected by members of the Scottish Labour Party. That is who I’m accountable to.
“They elected me back in 2017 to lead the Scottish Labour Party into the May 2021 Scottish Parliament elections. That is what I am on course to do.”
Mr Leonard said he had received “a huge number of messages of support” from across the party and trade unions.
He added: “I am confident that I’ve got the backing of the members of the Scottish Labour Party who elected me just under three years ago to lead this party.”
James Kelly resigned as Scottish Labour’s justice spokesman earlier this week, saying he had no confidence in Mr Leonard’s leadership.
Social security spokesman Mark Griffin has also quit, with backbenchers Jenny Marra and Daniel Johnson adding their voices to calls for Mr Leonard to go.
Mr Leonard took over the leadership from Kezia Dugdale in 2017, and was seen as being close to then-UK Labour leader Jeremy Corbyn.
But there have been concerns about his performance from some senior party figures ever since.
Opinion polls suggest Scottish Labour is trailing a distant third behind the SNP and Scottish Conservatives ahead of the election next May.
The party slumped to fifth in last year’s European elections after winning just 9.3% of the votes – down from 26% in the previous election in 2014 – and lost all but one of its seats in last year’s general election.
And there are fears from pro-UK campaigners that another poor performance by Labour in next year’s Holyrood election would increase the chances of the SNP winning a majority.
Mr Leonard said he had inherited a party in third place and did not underestimate the scale of the challenge it faced, but that he had “faith in the values that we stand for and I’ve got faith in the policy ideas that we will offer the people”.
He added: “I think the political environment is changing because of the pandemic, I think people are re-evaluating their priorities.
“I am sure as people get nearer to the election next year they will understand that the next five years, the next Scottish government and the next Scottish Parliament’s priorities will need to be on recovering the economy, tackling the jobs crisis and investing in public services like our National Health Service.
“I am convinced that when we get closer to the election and the policy agenda is defined, more and more [people] will turn to the Scottish Labour Party.”
Mr Leonard has been backed by Scottish Labour figures including MSP Neil Findlay, who is also on the left of the party.
Mr Findlay tweeted that the colleagues who were calling for Mr Leonard’s head were “pathetic” and guilty of “treachery with a snarl”.