The Dominican Sisters of Eastern Australia established St Mary's School for the deaf at “Delgany” Portsea in 1948. It was the first oral school to be opened in Victoria. The school opened in January 1948 with an enrolment of 50 pupils. The school was a residential and day school. In 1950 a kindergarten was provided for 3-4 year olds.
By 1952 audiologists and technicians from the Commonwealth Acoustic Laboratories were visiting every month to check the children's hearing aids. Loop systems were introduced in the lower grades and Group H hearing aids in the senior grades. Music was an important part of the curriculum to develop speech. Delgany provided the students with a rich environment of activities including ballet, golf lessons, handcraft, cubs, Red Cross and Scottish dancing.
In 1968 a limited program of integration began with Sorrento Catholic and State primary schools.
Cued Speech was introduced in 1970 following a visit to Victoria by Dr Orin Cornett.
In 1980 the number of students began to decline as families chose to send their children to day facilities nearer their homes. As a result, a working party was established and in 1983 a decision was taken to relocate the school to Melbourne.
In 1984 a class of four students enrolled as St Mary's students at St Scholastica's school in Bennetswood awaiting the relocation of the school.
In 1985 the school was renamed St Mary's School for Children with Impaired Hearing after it made the historic move to Melbourne with the kindergarten and primary campus located in St Mary's building alongside the newly established Holy Trinity school and the secondary campus was located within St John's Regional College, Dandenong. A boarding house named 'Delgany House" was established for eight boarders in Wantirna.
Our third campus was opened in 1997 at Aquinas College in Ringwood with six students.
The school's name was changed to St Mary's College for Hearing Impaired Students in 2003. Also in the same year after much deliberation and discussion the ownership of the college was passed from the Dominican Sisters to the Archdiocese of Melbourne.
In 2008 St Mary's established a fourth campus within Marymede Catholic College in South Morang. This campus provides enrolments from Prep to Year 12.
In 2016, a fifth campus was establish in Sunbury in partnership with Salesian College with 7 enrolments, opening educational opportunities for students with a hearing loss in the north-west of Melbourne.
In 2017, the College was renamed St Mary's College for the deaf as the term ‘deaf’ was considered to encompass both ‘hard of hearing’ and ‘Deaf’ students and is internationally considered a more positive and matter of fact statement than using the term ‘impaired’ which implies a deficit.