The main campus, IJA-Marikina, is located in the residential community of Rancho Estate, bounded by SSS Village in Marikina City. Its formal operations began in June 1979 with the opening of classes for 127 Pre-School pupils and it was formally incorporated as a non-stock, non-profit corporation in February 1980. The following academic year, classes for Grades 1-4 started and the first batch of Grade 6 pupils graduated in March 1983. Government recognition for the Elementary Course was granted in the same year.
Many parents requested the school to organize a High School Department, and so in June of 1983, the IJA High School started operations, with government recognition granted in 1986. The first batch of High School graduates received their diplomas in 1987.
The active involvement of the parents in the development of Infant Jesus Academy was evident since the school’s beginnings with the first IJA Family Council (IJAFC), the association of parents, teachers and guardians of IJA students, formally organized in 1980. Since then, the IJAFC has been a steadfast partner of the school administration in improving the school’s facilities and programs.
The mid 1990’s witnessed a rush of construction to improve the school’s instructional facilities in this campus. Its three-storey building that currently houses the classrooms and offices was completed in 1993. More land was acquired by the school in 1995 which enabled the administration to build the area which is now occupied by the computer laboratory, the HE laboratory and canteen. A four-storey structure which houses among others, the school chapel and the library was constructed in 1997, and in commemoration of the school’s 20th anniversary, the chapel was renovated in 1999. To mark the school’s Silver Jubilee in 2004, its quadrangle was renovated and now called the Jubilee Quadrangle. In 2006, its science laboratory was improved to enhance the Science instructional program. When the school celebrated its Pearl Anniversary in 2009, the school façade in the main campus was renovated to mark this event.
While continuously improving its facilities, the IJA system of schools always set as its utmost priority, the continuous development of its instructional programs by seeking accreditation from reputable accrediting organizations. In February 2005, the High School level of IJA-Marikina was granted applicant status by the Philippine Accrediting Association of Schools, Colleges and Universities ( PAASCU), making it the first co-ed school in Marikina to receive such a status. In 2008, it became an accredited member school with Level I status. Its Elementary Level underwent the consultancy visit and the preliminary survey in 2009 and 2010, respectively, and was granted applicant status in 2011.
In addition, in 2006, IJA-Marikina was admitted as a member of the Catholic Educational Association of the Philippines (CEAP). In the same year, it underwent a certification program conducted by the Fund for Assistance to Private Education (FAPE) which enabled the school to secure tuition subsidy for its high school students under the Education Service Contracting (ESC) of the Government Assistance to Students and Teachers in Private Education (GASTPE) program. The school’s participation in this program provided training opportunities for teachers and administrators which ultimately benefited the students.