The headmaster of elite Sydney private school Cranbrook has resigned days after a media report claimed there was a toxic culture at the boys school.
Nicholas Sampson stepped down on Friday, the ABC reported, following the airing by the broadcaster of claims against the school by former female teachers and staff.
The headmaster reportedly resigned after revelations he kept a male teacher on staff who had sent sexually explicit emails to a former female student of a girls school where the man previously taught.
Mr Sampson's resignation followed "allegations of extremely concerning past conduct matter involving a current senior school teacher at Cranbrook", the school's council said in a statement.
"The circumstances of the matter and subsequently Mr Sampson's failure to disclose the matter to the current school council in the context of this week's ABC Four Corners broadcast have led to an irrevocable breakdown of trust between the headmaster and the school," it said.
"The council communicated this to Mr Sampson this morning and received his resignation."
Junior school head Michele Marquet had been appointed acting principal in the wake of the "unsettling" events, the statement said.
Cranbrook's website no longer lists Mr Sampson, a former headmaster of Melbourne's prestigious Geelong Grammar School, as part of its executive team.
The ABC's Four Corners program on Monday detailed allegations of workplace bullying and abuse at the eastern suburbs school.
The controversy comes as the school, single-sex since it opened in 1918, gears up to admit girls from 2026.
In the wake of the claims, former tennis star Jelena Dokic reportedly backed out of an appearance at the school ahead of International Women's Day.
On Cranbrook's website, Mr Sampson says the school builds academic curiosity and optimism in "each of our students, allowing them to thrive in the 21st century".