Zachariah Keodirelang Matthews, was born in Kimberley in 1901, the son of Peter Motsielwa and Martha Mooketsi Matthews, a Tswana mineworker who later opened a cafe. Though exposed to politics at a young age - his father was a Cape voter and his cousin, Sol Plaatje, a founder member of the African National Congress (ANC). Matthews devoted the first part of his life exclusively to education.
He enroll at Fort Hare University and in 1923 became the first African to obtain a B.A. at a South African institution. Z.K. did not confine himself to academic studies; he combined his study of anthropology and the law with an active political involvement. He found his true political home in the ANC. He had attended meetings of Congress as a boy in the company of Sol Plaatje, but it was only in 1940 that he became a member of the organisation.
In 1943 he was elected to the National Executive Committee and at the same time he became a member of the Native Representative Council, a purely advisory body that has been condemned as a "toy telephone" and which Z.K. found generally frustrating, although he found dealing with the Native Education Act of 1945 a "valuable experience" not for the process but for the people he met. In June 1949 Z.K. succeeded James Calata as ANC provincial president in the Cape. In 1966 he accepted the post of Botswana ambassador to the United States and he died there in Washington in May 1968.
Verwey, E.J. (ed)(1995). New Dictionary of South African Biography, v.1 , Pretoria: HSRC, p. 163.