In 1948, the parish of Sefton was established and placed in the care of the Oblate Fathers of Mary Immaculate. The first parish priest, Fr Dan Breslin OMI, worked hard to establish a parish school. He was rewarded when two Sisters of St Joseph from the Lidcombe community arrived in May 1950. The school began in the church hall with 48 pupils.
The school developed as a primary school for girls from Kindergarten to Sixth Class and for boys to Fifth Class. Immaculate Heart of Mary School is a systemic co-educational primary school, for boys and girls from Kindergarten to Year 6.