The First Minister made the significant apology days after pupils protested and calls were made for Education Secretary John Swinney to resign.
At her regular briefing, Sturgeon said: “I do acknowledge that we did not get this right and I am sorry for that.”
The U-turn comes after defending a system brought in to grade pupils who were unable to sit normal exams because of the Covid-19 health crisis.
Teachers’ estimates were “moderated” by the Scottish Qualifications Authority. But it emerged pupils from poorer areas were more likely to be downgraded than peers in more affluent communities.
A furious backlash led to pupil protests in the centre of Glasgow and widespread despair from every political party, including among senior SNP members.
Sturgeon, who had defended the system until today, said she still has confidence in Swinney, who will make a statement on the next steps on Tuesday.
But she made clear downgraded pupils will not be expected to appeal every downgraded result – a responsibility she said falls to the Scottish Government.
In a statement on the shambles, Sturgeon said: “We will be taking steps to ensure every young person gets a grade that recognises the work they have done.
“In a very difficult and unprecedented situation we took decisions that we thought, on balance, were the right ones and we took them with the very best of intentions.
“These were broadly the same decisions that had been reached for England and Wales. Our concern, which was to make sure the grades young people got were as valid as those they would have got in any other year perhaps led us to think too much about the overall system and not enough about the individual pupil.
“That has meant too many students felt they have lost out on grades they should have had, and also that it has happened as a result not of anything they’ve done but because of a statistical model or algorithm, and in addition, that burden has not fallen equally across our society.”
Sturgeon continued: “Despite our best intentions, I do acknowledge we did not get this right and I’m sorry for that. But instead of doing what politicians sometimes do and dig our heels in, we are determined to acknowledge that and put it right.”
Sturgeon said there are “deeper questions” about the impact of exams on the attainment gap and on the difference between exams and teacher judgement.
She added: “The most immediate challenge is to resolve the grades awarded to pupils this year. We will set out our approach tomorrow to the Scottish Parliament, but let me be clear we will not expect every student who has been downgraded to appeal.
“This situation is not the fault of students and so it should not be on students to fix it, that’s on us.”
Earlier, the Record revealed how 38 per cent of results had been downgraded at Sturgeon’s former school, Greenwood Academy in North Ayrshire. The region’s worst affected school, Ardrossan, had 50 per cent of results marked down by a grade or more.
We also revealed pupils at St Joseph’s Academy, in Kilmarnock, saw 51 per cent of results marked down in a move branded “completely unjust”.
The one-off moderation system relied on teachers’ estimates which were then looked at an adjusted by the SQA. People in the most deprived areas of Scotland had results downgraded by 15.2 percentage points compared with 6.9 in the wealthiest areas.
Sturgeon confirmed no one who had their grades marked up by the SQA from initial teacher estimates will have their results marked down as a result of today’s change of policy.