During the Spanish colonial period, Teodoro Santos and Africa Ventura constructed a building in downtown San Fernando.

Adjacent to the main building was a domestic science structure, costing ₱3,500, which stood on the grounds and formed an integral part of the institution.

Upon completion, the high school comprised nine classrooms, a library, a property room, a principal’s office, and an assembly hall spacious enough to accommodate four hundred people.

One of the early alumni of the school who gained prominence was Diosdado M. Macapagal, a graduate of the class of 1929, who later ascended to the position of the 5th President of the Republic of the Philippines.

Subsequently, the burgeoning student population prompted the national government to undertake the construction of a new building along Teopaco Street, popularly known as the High School Boulevard, its present location.

The Gabaldon Building, with its rectangular shape, showcased intricate sculptures and relief of human figures on its facade and rear.

PHS is one of the few remaining schools with Gabaldon architectural structures, holding the distinction of being the central landmark of the American public educational system in the province of Pampanga.

In its new setting, PHS continued to provide education to a growing number of students from various towns of Pampanga and neighboring provinces.

Subsequent typhoons, including Huaning, Isang, and Konsing, inflicted devastating losses and prolonged severe weather conditions in Luzon.

The Gabaldon building, the school’s primary structure, was partially submerged, with its basement remaining waterlogged for an extended period before being permanently sealed.

In 1991, the eruption of Mount Pinatubo had a significant impact; however, the floods triggered by "Bagyong Mameng" (Typhoon Sibyl) in 1995 had an even more profound effect, inundating the town, including PHS.

Floodwaters and mudflows from Mount Pinatubo cascaded into the town, causing severe damage to the school, with many of its buildings suffering immense devastation.

Following the campus upgrade, nearly all the buildings underwent rehabilitation and improvements, a collaborative effort involving various stakeholders, including administrators, students, teachers, non-teaching staff, alumni, PHS-MPCI, PTCA, NGOs, and GOs.