Blaenau Gwent has become the first Welsh local education authority to go in to special measures after a report found "systemic" management failures.
Education Minister Leighton Andrews said a task force led by Neath Port Talbot council will be brought in.
Blaenau Gwent, which accepted change was needed, must now provide an immediate action plan for its 34 schools.
Mr Andrews said the shortcomings are "quite simply unacceptable".
"Scrutiny of education by elected members has too often been undermined by political point scoring.
"This has meant education officers and head teachers have not been held accountable for poor performance, effectively letting them off the hook.
"Much of Blaenau Gwent is of course severely deprived. That means that a small council faces significant challenges across all of the services it provides, " Mr Andrews said.
"But that cannot be an excuse - there can be no excuses for letting children and young people down this badly"
Blaenau Gwent's executive member for education Stephen Bard has stood down.
According to Estyn, the education inspectorate for Wales, an authority is placed in special measures when it fails to give pupils an acceptable standard of education, and the people responsible for leading, managing or governing it do not have the ability to make the necessary improvements.
Estyn's report found that children and young people in Blaenau Gwent "do not make good progress" and that standards "are well below what is expected".
Support for school improvement and additional learning needs was unsatisfactory, the report found.
Estyn found the authority had unsatisfactory prospects for improvement because senior officers and elected members of successive administrations had provided unsatisfactory leadership.
Managers did not evaluate the impact of initiatives or target resources to learners with the greatest need, and leaders and managers had a track record of "slow and incomplete" responses to recommendations from successive Estyn inspection reports.
It the first Welsh council to receive an overall "unsatisfactory" judgment since Estyn introduced a new inspection regime last year.
Dr Philip Dixon of the Association of Teachers and Lecturers (ATL) said the report made "disturbing reading".
"We are talking about the futures of the children in one of the most deprived parts of Wales," he said.
"The local authority is obviously too small to deliver effectively and the report is another filip for those who want to see education delivered on a more effective consortia basis.
"It also shows the catastrophic effects of long term failures in political leadership, and an apparently revolving door in regard to senior management."
However, Dr Dixon said the report also raised more questions than it answered as Welsh Government data recently showed Blaenau Gwent was the third best performing authority in Wales in terms of "value added".
Blaenau Gwent leader Des Hillman said the council was already working with other authorities to raise standards.
He said: "Progress has not been as fast as we want, and more needs to be done.
"The tough decisions we have already taken mirror the clear direction set by the education minister and the Welsh Government's policy directives but clearly we need to do more.
Denbighshire was placed under special measures in 2007 under a previous Estyn framework.