The parish of Our Lady of Good Counsel Mourne Road was established on the 9th April 1943 by the Archbishop of Dublin Most Rev John Charles McQuaid DD. Rev Fr Eugene Trainor CC St. Michael's Parish Inchicore was appointed first parish priest.

The Sisters of Mercy arrived in the parish on the 3rd January 1944. They had been asked to undertake the management of and to teach in both the Infants' and Girls' School. Boys National School also opened at this time. Fr. Burke the parish priest of Rialto planned the new schools-to consist of three primary schools grouped together in the centre of the new parish of Drimnagh. There would be a mixed Infants' and Girls' School to be managed by the Sister of Marcy and Boys' School to be managed by the parish.

World War II was well under way when this development was talking place. Building materials of all kind were scarce and expensive, yet the schools were completed ahead of schedule. At the time, the Drimnagh National Schools complex was regarded as one of the biggest and most modern in Europe. 

The minister of Education, Mr Thomas Derrig officially opened the convent schools on the 10th January 1944. Due to the large scale of the project the event was given extensive coverage by the national newspapers. The Evening Herald reported "the space covered by the schools-one of the finest in Europe-extends over 7 acres. In the Girls' School there are 44 classrooms and in all 76 rooms. In the Boys' School which adjoins the Girls School there are 22 classrooms and 37 rooms altogether."

The combined enrolment of the three schools was over 3,800 pupils. They were considered to be the largest schools in Europe at the time. However, so great were the numbers of children in the area at the time that no child under the age of six could be enrolled. 

In 1956, the Sisters of Mercy extended the National School, to provide some secondary schooling for girls, offering post- primary education.