Mandeville Hall is a fine example of the mansions that appeared in Toorak in the second half of the 19th century. The original two-storey, 12-roomed brick residence, first known as St George's, was designed in 1867 by Joseph Reed for the merchant and soft-goods trader, Alfred Watson. In 1876 the house was purchased by the wealthy landowner and businessman Joseph Clarke. Renamed Mandeville Hall, after Norton Mandeville in England, it underwent substantial additions designed by Charles Webb.
In 1924 Mandeville Hall became part of the Loreto Convent (IBVM). The Loreto Sisters transformed the old building into a Catholic school for girls. By 1925 four senior classrooms had been constructed as well as tennis and basketball courts. At first the Oak Parlour had been used as a chapel but in 1928 a new chapel was opened by Archbishop Mannix. This was followed in 1932 by music rooms, more classrooms, the green verandah and an art room. Three years later second-storey dormitories and classrooms were added. The kindergarten was opened in 1935 and the neighbouring Delprat's house was purchased to house the junior school and facilitate the completion of a science block in the senior school. In subsequent years the library, gymnasium, administrative facilities and swimming complex have been added to the school.
Initially the living conditions experienced by the nuns had been rudimentary - some resided in the boarders' quarters while others slept in the stables. It was only in 1959 that a residential convent wing was completed.