Built-in 1939 as Henry Harbin Senior School, the school has expanded in every decade since its opening. The school was originally two separate schools - girls on the eastern side, boys on the west, separated by a quadrangle in the centre of the main school building. This layout was almost exactly the same as the original building at Kemp-Welch School, which opened in 1938. The school became a mixed school for 12- to 16-year-olds in the 1970s, reverting to an entry age of 11 in September 2013, as part of Poole's re-organisation into a two-tier education system. In the late 1980s the school became a 'technical high school', and its name was officially changed to Poole Technical High School in the early 1990s. It was during this period that the school added a sixth form and introduced an academic express stream, with a particular focus on the teaching of 'triple science' qualifications. It is one of a small group of partially selective schools that were permitted to retain selection under the provisions of the School Standards and Framework Act 1998.
Recent developments have included the new main school canteen, an English block, extensions to the Art and Science blocks, and the Merchants' Hall, which includes a canteen for the sixth-form and seminar rooms. From September 2013, the school has admitted students in Year 7, taking the total number of students in attendance at PHS to over 1900, making it one of the larger schools in the country. Work completed over summer 2014 focused on extending the life of the newly named "Shaftesbury Centre". The name of the building was chosen to honour the 9th Earl of Shaftesbury, who opened the school in 1939. In September 2019 Poole high school officially turned on its PV system, 592 panels generating 185 kWh of electricity.
School houses
Every student is assigned to one of the six houses at Poole High School. In every house, there are two registration groups per year.
Jolliffe
Garland
Lester
Masters
Thompson
White
Before the school year of 2017, there were an additional two houses, Spurrier and Harbin, the latter named after the school's founder. However, these two houses were abolished in favour of creating a Year Eleven office, which replaces the house system for GCSE-year students. The students in Spurrier and Harbin from Year Ten and beneath were distributed into the remaining houses, and the new Year Eleven students from all houses were put into the Year Eleven group. As of the 2017 school year, the house systems were abolished and the students were divided into year groups. Houses are only currently used for Sports Day activities at the Poole High School.
