The Armidale School (TAS) principal Murray Guest has died, after a car accident on Tuesday morning.
The 125-year-old New England boarding school, which includes students from the local region in its alumni, released a statement to parents and the wider school community confirming the "gravest gravest and most devastating news".
The chairman of school board Sebastian Hempel paid tribute to a man he has described as "an outstanding leader, educator and friend".
Mr Guest, 59, was the sole occupant in a vehicle involved in the single car accident outside Armidale, on the Waterfall Way.
"Murray was appointed as the school's 13th Headmaster in 1998 and set it on the course on a new direction with vision, energy and purpose," Mr Hempel said.
"Strategically his most defining legacy was the introduction of full co-education in 2016, but more enduring will be the impact he has made on generations of boys and girls who received their education under him.
"Whilst there will be many wishing to pay their respects to his memory, our primary thoughts and prayers are with Murray's wife, Joanne, and their two children, for whom the whole school community is united in its support.
"We would ask that the privacy of the school community be respected at this time."
Deputy headmaster, Alan Jones, said the news was devastating for the school community, particularly staff and its 620 students.
"But in particular our prayers and thoughts are with his family, his wife, Joanne, and his children, Annelise and Harry," he said.
"The TAS community is united in our grief and devastated by this news.
"We are aware of the emotional impact this news may have on all of you.
"We are providing initial support to our students through our welfare team.
"I assure you that while this news is heartbreaking and incomprehensible, our board and staff will continue to guide the school during this very sad time."
Northern Tablelands MP Adam Marshall also paid tribute to Mr Guest on Tuesday.
Mr Marshall said he joined with many people in the community who, upon learning the news, sat in quiet shock and disbelief, wishing it was not true.
"That someone with such a passion for education and innovation and a leader of the highest calibre has been taken so suddenly is a blow to us all and a huge loss to the community," Mr Marshall said.
"My thoughts at this moment are with everyone in Murray's two families - his TAS family - a huge group of people, of all ages, stretching across the globe and most of all, his own family, wife Joanne, children Annelise and Harry, and other close relatives.
"They generously shared Murray with TAS and the wider community for many years. We thank them for that and reach out to support them at this very sad and distressing time.
"The Armidale and educational community will mourn the loss of a fine man and educational leader and will remember and cherish all the good that he has done and the legacy he leaves.
"Murray has and will continue to always inspire the best in students and teachers alike," he said.
New England MP Barnaby Joyce also paid tribute to Mr Guest.
"This is a huge shock to the whole New England community and to his family, they carry the heaviest burden," Mr Joyce said.
"There is nothing that can really be said that lightens this load, but all who were affected by Murray's life will be devastated by his loss.
"My thoughts and prayers are with the family and for Murray," he said.
Mr Hempel said staff, students and parents were advised of the tragic news on Tuesday afternoon.
Students were informed at an all school assembly before being counselled in their pastoral care groups.
Further counselling will also be made available to students and staff, the school said.
Police have confirmed investigations into the crash are continuing.