Mukangu Boys’ High School was started immediately after independence through concerted effort made by a group of residents. These included the late David Gichora, late Gidraph Ndegwa, late Joshua Kiuma, Hilda Wanjiku Amon and late Beth Muthoni Ngari. The five first met in 1960 and came up with the idea of starting a secondary school. The idea did not materialize until Gidraph Ndegwa Warui, who was the then chairman of Mukangu Primary School, mobilized parents and held a harambee for the establishment of the secondary school in 1965. The harambee was attended by Hon. Fred Kubai who was an Assistant Minister in Kenyatta’s Government. After the fundraiser, permanent classrooms were built in the primary school.
The Assistant Education Officer, Mr. Chege, directed that an alternative site be sought for the secondary school as it was not supposed to be built on the primary school land. In 1970, a village adjacent to the primary school was dissolved to create a plot for Mukangu Boys’ High School. In 1972, the school was officially registered with the assistance of Mr. Josphat Mutugi, the then Labour Commissioner and a member of the community.
The school started offering exams in 1970, offering K.J.S.E, K.C.E and K.C.S.E. Mukangu Boys’ High School was registered as a government school in 1983. Many graduates of the school have joined institutions of higher learning and the wiser community to participate in nation building.
From 2009, the school became Mixed Day and Boarding for both boys and girls. In February 2018, the school was registered as a County Boys’ Boarding School and started phasing out all the day-schooling girls and boys and became a fully Boys’ Boarding School. It was upgraded to the Extra County Boys’ Boarding School level in 2022.