John O'Neill, 49, currently the school's senior deputy rector, will take over in August 2015 on the retirement of Colin Mair from the independent school.
Mr O'Neill, a graduate of Glasgow University, has over 25 years' experience in schools in Glasgow, Edinburgh and London.
He joined the High School senior management team in 2004 from Merchiston Castle School on Edinburgh where he was housemaster and head of sixth form.
In his current role as senior deputy, Mr O'Neill's responsibilities include being in charge of the fifth and sixth years, the Ucas application process, the Scottish Qualifications Authority exam arrangements, and three successful reviews of the school's Investor in People status.
In a letter sent to school parents today, Mr Brian Adair, chair of the High School of Glasgow board of governors, said: "The governors are confident that under John O'Neill's leadership the school will maintain its current ethos and high standards of education in the future. He has a very close knowledge of the High School, its ethos and traditions, both as senior deputy dector and as a parent."
The High School has 680 pupils at its senior school based at Anniesland and 360 pupils at its junior school and kindergarten at Bearsden. Founded as the Choir School of Glasgow Cathedral in 1124, it is the oldest school in Scotland and the eleventh oldest in the UK.