Canon Donal Cregan, Parish Priest, established Scoil Cholmcille in 1975 in the Parish Hall beside Ss. Alphonsus and Columba in Ballybrack village. The school then moved to a greenfield site in Ballybrack in south Co. Dublin. Mr. John Dennehy was appointed as Principal Teacher. The school was then a group of prefabricated buildings. Gradually pupil numbers grew and correspondingly staff members. Permanent buildings were put in place but as the numbers of pupils continued to increase, the need for more permanent building was addressed. The school was added to and developed to its present size. When the pupil numbers reached close to one thousand and the school was divided into a Junior School and a Senior School. The Junior School catered for pupils ranging in age from four to eight years of age in 1979. The Senior School catered for pupils from eight to twelve years of age.