Headteacher of Watford Grammar School for Boys, Martin Post, is to leave after being appointed one of eight Regional Schools Commissioners (RSCs) by the Department for Education.
He will have responsibility for overseeing the growth of academies in the North West London and South Central region and will monitor their performance with a brief to ensure children receive the best possible education.
He will work closely with national Schools Commissioner, Frank Green, and Education Secretary Michael Gove to shape the role and priorities of the growing numbers of academies.
He will be taking up his new position from September 2014. Mr Post, a former student and headboy at the school during the 70s, said: "I am very excited by the prospect of this next stage in my life, but it will be very hard indeed to leave this wonderful school.
"I’ve been here as a teacher since 1995 and was lucky enough to become headmaster in 2000.
"I have enjoyed working with everyone here and have been inspired every day by the commitment and talents of the students and the staff, past and present."
Under his management the school has had successive outstanding OFSTED inspections and has consistently appeared in the Financial Times Top 100 Schools.
The Sutton Trust recently named Watford Grammar School as the leading state school for Oxbridge and Russell Group university entry.
Since 2004, he has managed the £20m self-financed redevelopment of the school site and its transformation to an Academy Trust.
He is a National and Local Leader of Education and a Member of the Wellcome Trust working group on Developing Governance in Schools. He has been a Consultant Headteacher for several schools both in Hertfordshire and Essex.
He is Trustee of the Teacher Development Trust and the Watford Fuller Foundation. He is also Director of the Academy Company for Watford Grammar School for Girls.
The school’s Chair of Governors, Paul Shearring, said: "I’d like to congratulate Martin on his well-deserved appointment and thank him for his outstanding work over the past 14 years as headmaster.
"He has transformed the school site and has ensured the school’s outstanding academic reputation continues into the future.
"We will begin the recruitment process for a new headmaster in May.
"The school’s deputy headmaster, Mark Allchorn, will take over as acting headmaster until such time as a suitable successor is appointed by the Governors."
Mr Allchorn joined the school in 1981 as a teacher and has been deputy head since September 2003. He was recently acting headmaster at Rickmansworth School.