Firbank was established in 1909 as a day boarding school for girls, by the Anglican Archbishop of Melbourne, Henry Lowther Clarke when he was left a legacy for ‘educational purposes’. He purchased the property, Gawsworth, which stretched between Outer Middle Crescents established a school for girls. He named the school after his birthplace in Westmorland, England. He gave the School his crest as Archbishop chose the motto, Vincit qui se vincit (She conquers who conquers herself). As enrolments grew, under the leadership of Miss Maud Cameron, who was Headmistress for 43 years, further lwas purchased, including the Pen-y-bryn estate Atherstone in Sandringham.

　　Founded on Christian principles, Firbank has always maintained a strong connection with St Andrew’s Anglican Church, Brighton All Souls Sandringham where formal school services are held

Sandringham House, originally called Atherstone, was founded in 1896. In 1932, it became a part of Firbank. Sandringham House became a fully co-educational Junior School of Firbank in 1994. Since that year, the number of boys has grown progressively. Currently boys number 45% of the student population.

　　Girls have a guaranteed pathway to Firbank's Senior School in Brighton while boys have a guaranteed pathway to our brother school, Brighton Grammar School.