He has called on the Scottish Government to act “decisively”, proposing a five-point plan to reform teaching.
The former teacher was speaking ahead of a lecture to the Moray House School of Education at the University of Edinburgh on Thursday.
The former Scottish Labour leader said: “Piecemeal change, complacency and political spin must no longer be tolerated. It is time for honesty and action.
“Our children and young people have had a terrible year in 2020 so let’s resolve to give them hope from 2021.
“An education system that might someday be a world leader again would be a good start.”
The former Scottish Labour leader, who was first minister from 2001 to 2007, said there must be “no more clarification of Curriculum for Excellence”, saying instead a “radical shake up, implemented decisively, is now required”.
“We must put the acquiring of knowledge, proof of attainment and freedom for schools to innovate back at the core of the system.”
Lord McConnell, who was education minister before becoming first minister, said it has been 20 years since he was “given the task of rebuilding morale, standards and ambition in Scotland’s schools”.
He added: “For a former teacher it was the job I had dreamed of.
“In the year that followed, we put the teacher back at the heart of the system and started on the road to recovery and world class education in Scotland again.”
Under that system, he claims Scotland had “higher quality in the classroom and better recruitment”, with universal access to areas such as music education.
He said: “Twenty years on, there are real problems again.
“Even before the Covid-19 pandemic, morale was falling, Scotland was falling behind other countries in the UK and across the world, a large number of disadvantaged kids are failed by the system every year and the new Curriculum for Excellence has made matters worse.”
He said there now needs to be “targeted action to improve the life chances of those most disadvantaged and vulnerable”, suggesting they should get access to mentors and tutors as well facilities for homework and access to technology.
A Scottish Government spokesman said: “Curriculum for Excellence (CfE) ensures children and young people have more options in their education, and that their wider achievements and skills are recognised alongside qualifications.
“More young people are achieving at least one Higher or equivalent compared to when CfE was introduced, the number of school leavers who went on to positive destinations such as work, training or further study increased to a record 95% in 2018-19, and 64,274 skills-based qualifications have been awarded this year – up from 37,106 in 2014.
“The breadth of learning delivered by CfE – which helps equip pupils with the knowledge, skills and attributes needed for life in the 21st century – was reflected in the recent PISA global competence assessment, where only two countries achieved a higher average score than Scotland.
“We have commissioned the Organisation for Economic Co-operation and Development to carry out an independent review of the curriculum which will report next year.”