Designed by the New Zealand architect William Cumming, Pridham Hall was built between 1918 and 1919 by Boon Bros of New Plymouth and it was for a very long time the main building of the school.

After an incident in 2008 when a boarder was attacked by four other students[16] the school's board of trustees commissioned an independent report on bullying in November 2008.

[18] Idol winner Stan Walker, musicians Matt Thomas, Hayden Chisholm, former Chief of the Royal New Zealand Navy Rear Admiral Tony Parr,[19] David Gauld (president of the New Zealand Mathematical Society 1981–82), the author and journalist John McBeth, and 24 All Blacks graduated from New Plymouth Boys' High School.

[citation needed] In 2018, Professor Emeritus David Penny was named a foreign associate of the National Academy of Sciences (NAS).

[20] Members of Parliament who attended the school include Andrew Little, John Armstrong, Bruce Beetham, Merv Wellington, Cam Calder and Ken Comber.

[23] Australian media personality and Senator for Victoria, Australia Derryn Hinch attended New Plymouth Boys' High.