Adisadel was established in 1910 in a storey building at Topp Yard, near Christ Church and Cape Coast Castle. It began with 29 boys; in 1935 it had about 200 boys; at the time of the Golden Jubilee in 1960, enrolment had gone up to 545; and now in 2007 there are over one thousand five hundred (1500) boys (all boarder). There are 93 teachers of whom 15 are female.
The school’s Founder was the Right Reverend Dr Nathaniel Temple Hamlyn of the Anglican Church. His purpose was to provide a grammar school for sons of Anglican parents, in particular a training ground for Church personnel.
The School is the second-oldest secondary school in Ghana, and one of the most famous institutions of learning in sub-Saharan Africa. The first secondary school to be established in Ghana was Mfantsipim School, also in Cape Coast, which was founded by the Methodist Church in 1876. It currently boasts of 10 houses, the most recent being Thomas Jonah House, which was built in 1997.
Adisadel College was the first secondary school in the history of Ghana to have its prefects don special cloaks; red cloaks for the head prefects, blue for the other prefects and green for the assistants.