Since it was completed in 1919 Pridham Hall has served as a symbol of New Plymouth Boys' High School.

The school was established by an Act of Parliament in 1878 and officially opened four years later on a reserve set aside for the purpose on the first plans of the city of New Plymouth. The first headmaster was Ernest Pridham, a Master of the Arts graduate from Dublin who ran the school until his retirement in 1911. The school became increasingly popular after this date following the establishment of boarding facilities, an official uniform, and the segregation of girls, first admitted in 1885, from boys. Attempting to overcome the perception of the school as a class institution for sons of wealthy farmers, the headmaster had also made it known that no boy would be refused entry provided he was of good character and had an incentive to work.

In 1916, three years after girls attended the school for the last time, a disastrous fire started in the school gymnasium and destroyed the main buildings of the school. Temporary accommodation was found in the nearby racecourse buildings until the new building envisaged by Headmaster William Moyes and the school board could be erected.

It was agreed that the new building should be a comprehensive complex that would include all the facilities required by the growing roll and embody the spirit and rich prospects of the school. The board applied to the Institute of Architects for a suitably eminent architect to design the building. The president, William A. Cumming, was selected. As the official architect for the Auckland Grammar School Board, Cumming had considerable experience in designing buildings for educational purposes. The cost of Cumming's proposal was £12,350 and as the board only had £3500 insurance money, it applied to the Government for the remaining funds. The government, still recovering from the vast expenditure on defence during the First World War, refused to grant the amount requested. Months of negotiation resulted in an agreement that the government would provide just £5000 towards the costs, which meant that 'luxuries' such as the assembly hall, west wing and the bell tower would have to be omitted. Convinced that a hall was an integral part of a school, Moyes initiated a public appeal that resulted in sufficient funds to erect both the hall and the west wing of the building.

Construction started in early 1918 and was completed the following year by Boon Bros. of New Plymouth. The two storey building is built side-on to the road and overlooks the cricket pavilion. Made of reinforced concrete with a roughcast exterior, the front façade of the building includes a large balcony designed to allow spectators to watch the cricket. The west wing of the building is dominated by a large Elizabethan style window. The east wing remained unfinished until the Napier earthquake of 1931 destroyed all hope of erecting the bell tower. It was then built to the same height as the west wing and capped with a battlement-like finish. The roof is of pressed metal tiles, a material meant to resemble the more expensive slate, and features a large roof lantern on the north façade. Edwardian Freestyle in design, the building includes several classrooms and laboratories built around a large assembly hall. Timber panelling and wooden columns are a feature of the hall. Named after the first headmaster, Pridham Hall was officially opened by Deputy Prime Minister Sir James Allen [1855-1942] in 1919.

Pridham Hall allowed the entire school to be taught in a single building. The assembly hall became the spiritual and physical heart of the school. Yet the school role continued to increase beyond all expectations of the school board, and in 1923, two extra classrooms were incorporated into the building. Three years later a fire destroyed the new classrooms in the east wing and badly scorched the roof of the assembly hall. The students were transferred once more to the racecourse buildings until the damage was repaired later that year, again by the Boon Bros. By 1927 an enlarged curriculum and increased number of students meant Pridham Hall could no longer contain the entire school. Extra classrooms were erected on the school grounds. By 1965 the assembly hall was too small to hold the entire school safely. Funds for a new hall were approved and the government agreed to contribute a larger amount than was usual towards the new hall as it had not been able to fund the full cost of the original hall. The first school assembly was held in the new building in 1972. Although the assembly hall in Pridham Hall continues to be used for house meetings, the building is now primarily a class-room block used for lessons in English, history, geography, and social studies. The building has been recently renovated and is in excellent condition.

Pridham Hall has national significance as the work of eminent New Zealand architect William Cumming. New Plymouth Boys' High School is one of New Zealand's best known secondary schools and, as the oldest remaining structure in the school and the primary building for the majority of the school's history, Pridham Hall is significant as the focus of the school's identity. The size and layout of the Hall is of historical interest as a indicator of the size of the school in the early twentieth century. Its unique façade is historically noteworthy as a permanent reminder of the financial stringencies practiced by the government following the First World War, and the assembly hall stands as testimony to the generosity and support of the local community.