St. Joseph School was founded in 1971 by the late Dr. Jose Lejarzo Mercado and Mrs. Eufrocina Ariano Mercado. It started as St. Joseph Nursery Center with only 18 pupils enrolled.
In 1972, a year after the school was founded, the founders themselves decided to start the school's grade school department which had its first batch of elementary school graduates in 1978. There were only 8 grade six pupils that comprised the first grade school graduates. Every year, thereafter, would increase in number.
Dedicated and commited to provide educational services to the children and youth of San Pablo City and its neighboring towns, cities, and municipalities, the school administration embarked on its expansion and development programs whith emphasis on the improvement of the school's physical plans and facilities as well. Academically, it has employed qualified teaching and non-teaching personnel with dedication and commitment to help and support the school's thrust in it's founders' mission of helpingthe children acquire good basic education.
In 1997, the school opened its academic doors to high school students, thus, started its high school department. Contrary to many secondary schools that began operating from first year high school, St. Joseph School started operating as a high school from third year level, thus, having its first batch of sixteen high school graduates in 1999.
Today, St. Joseph School is a highly recognized school, offering pre-school, complete elementary, and complete secondary levels. It is managed by a family corporation, SJS Inc., composed basically of the sons and daughters of the late founders Dr. Jose Lejarzo Mercado and Mrs. Eufrocina Ariano Mercado. It now stands as a monumental legacy of the dedicated founders and continues to live by their educational thrusts and integrity.