DES Smith was described by a friend as a top public servant who had transformed the lives of thousands of poor children.
Jon Cruddas, Labour MP for Dagenham in east London, spoke out in defence of the teacher at the centre of the police inquiry into "cash for honours" allegations.
He urged people not to judge Mr Smith on a 20-minute indiscreet conversation over a drink with an undercover reporter in which he suggested peerages and honours could be won in exchange for backing controversial city academies.
Those remarks led to Mr Smith resigning from the Specialist Schools and Academies Trust in January this year.
The 60-year-old is credited with helping turn around the fortunes of the poor performing All Saints Catholic School and Technology College in Dagenham. He was appointed head of its predecessor, the Bishop Ward School, a boys' comprehensive, in 1984.
It was, in his own words, "depressed and violent" and seriously undersubscribed.
In 1992 it merged with Sacred Heart, a girls' school, creating a co-educational voluntary aided comprehensive.
All Saints became one of the first specialist technology colleges in 1994 and secured 100,000 in extra funding, but fewer than a third of students were getting five or more A*-C grades at GCSE. By 2003, 89 per cent of All Saints students were getting these grades.
In the same year the school was judged the second most improved in England.
Mr Smith worked with Paul Grant, head at Robert Clack, also in Dagenham, to drive up standards at both schools.
A Specialist Schools Trust report in 2005, From Fighting and Failure to Shared Success, called them "two talented men who have stood side by side in a challenging situation and supported each other".