In 1887 Davidson-Houston was commissioned a second lieutenant with the 5th (Militia) battalion of the Royal Dublin Fusiliers.
[2] Davidson-Houston was assigned to the British South Africa Company Police, and was assistant commissioner in Mashonaland (1890–1892).
He was assistant inspector of Gold Coast Hausas (1894) and captain of the West African Frontier Service, Kwahu (1894–1895).
He served in the Fourth Anglo-Ashanti War (1895–1896), and in subsequent operations in the Gold Coast (1897–1898), and was acting resident Ashanti (1899–1900).
[2] Davidson-Houston married Annie Henrietta, oldest daughter of land agent Colonel Edmond Langley Hunt, C.M.G., of Curragh Bridge House, County Limerick (of a landed gentry family of Friarstown and Ballysinode),[4][5][6][7] and they had two sons.