Inception.In 1900, Rev. A.W. McGregor was sent by the Chuch Missionary Society (CMS)as a pioneer missionary to Kikuyu-Land, Rev Mc.Gregor was already involved in missionary work among the Taita in Taveta in early 1892.Thus Rev. Mc Gregor arrived in Fort Smith in Kikuyu on October 13 1990.He started looking for suitable land for missionary work. He had been offered land at site of Fort Smith bu declined due to its reputation for atrocities against against the kikuyu. He therefore went further afield in search of a suitable site. He finally purchased a parcel of land at Kabete locally known as Mayombo (the rocky place) from Cege Kanyi of Muthemba family. He took possesion of the site in 1901 and named it Kihuruko (a place of quiteness and rest). He started teaching the Word of God and literacy. By November 1901, he had five students. The local people nicknamed him "Kabora". It was on this land that Mary Leakey Girls High School really started.In eary 1902, Rev. MC Gregor was joine d by Rev. Harry Leakey who continued with the work. Rev MC Gregor later moved to Weitahaga in Muranga a few montyhs after Rev. Harry Leakey arrived, He was joined by his wife Mary, thier two little girls and a companion Miss Oakes. The locals nicknamed Rev. Leakey "Giteru" because of his bush beard. They were teaching a mixed group of boys and girls. However school work among women and girls was slow at first. In 1904 Miss Alicia Higgnbothan, a missionary from Mombasa, joned the Leakeys. She assisted in teaching catechism and also taught women who came for treatment from her tent. She taught them sewing and basic reading. In 1905, the Leakeys went on leave to England. Under Miss Higgnbothan, the girls class was slowly taking shape. The leakeys returned to Kabete in 1906 . Many boys had come to the school by then and the first two girl pupils were sister of aboy pupil and an orphan under his care. They lived with Leakeys and became the nucleus of the schools for they attracte dmore pupils.In 1909, Mrs. Mary Leakey opened a schoolfor girls which met on the veranda of her house.From that time, girls as boarders became a regular feature, for many came from up-country and others had run away from home for various reasons such as circumssion. Until 1921, Kabete was the only C.M.S. station with accomodation for boarders in Kikuyu County. The school however, never became regular due to intermittent illness of Mrs. Leakey.
In 1922, when Julia Leakey (her daughter) returned to Kabete after training in England as a teacher and a missionary in her own right, the school reopened on a regular basis.