On 1 December 1917, the former private home and vice-regal residence, Cranbrook, was bought at auction by an agent for Samuel Hordern.

He was the main financial benefactor of a group of businessmen and churchmen aiming to establish an Anglican boys' school in the Eastern Suburbs.

[12] From December 1917 to June 1918, a provisional committee of twelve, comprising the founders and six additional men, prepared for the opening of the new school.

They held meetings, ensured building renovations were completed, drew up the first articles of association and appointed the first Headmaster, Rev.

[15] In March 2024, the school was featured in a Four Corners investigation into allegations of a toxic workplace and sexist student culture, led by some former teachers.

The report also raised questions around Government funding for Cranbrook School and its level of accountability for this.

Cranbrook School offers the IB Diploma Programme as an alternative pathway to the HSC credential.

Cranbrook has an extensive range of co-curricular activities from the Arts to the Sciences, Music to Sport, providing its students with the encouragement to support their individual interests.

[21] Cranbrook has said it had built an improved and centralised incident behaviour register and strengthened its alliances with organisations including the NSW Jewish Board of Deputies.

A former teacher, who was blackmailed by a student saying he would claim she was abusing him if she did not send him sexual images, said that the incident was downplayed by Head of Senior School and Deputy Headmaster Bob Meakin, who allegedly stated that "because I'm young and, 'I'm just going to say it – attractive,' it's not [surprising] that I've received attention from the boys".