Gatu had been a member of both the central committee and the executive committee of the World Council of Churches (WCC) and was a vice-moderator of the WCC's Faith and Order Commission. Active in support of the WCC Programme to Combat Racism, he also served in high offices of the National Council of Churches in Kenya and the All Africa Conference of Churches. He was one of the key organizers of the 5th Assembly of the World Council of Churches when it was held at Nairobi in 1975.

Rev. Dr Olav Fykse Tveit, general secretary of the WCC, recognized John Gatu as "one of the pillars of African and world ecumenism over the past sixty years, a faithful and courageous champion of the East African Revival Movement" as well as "an agent of justice and peace." A sergeant in the colonial army prior to Kenya's independence, Gatu became a fierce advocate for liberation from western domination. In 1971, he advocated a "missionary moratorium" as proposed years before by German missiologist Walter Freytag.

Writing in the Dictionary of the Ecumenical Movement, John S. Pobee explained that the prososed moratorium called for a "complete halt in the sending of missionaries and funds from European and American churches to the churches of Africa, in order to enable African churches to develop their own identity and to define their mission for their time and place. Moratorium, as expounded by Gatu, was a challenge to the assumption that without the large-scale presence of western missionaries, Christianity could not survive in Africa."

Gatu encouraged the philosophy of Jitegemea (a Kiswahili word for "self-reliance") in the Presbyterian Church of East Africa (PCEA). As a leader of the PCEA, Gatu was instrumental in dialogue leading to the ordination of women, approved by the General Assembly in 1976.

Noted as an author of hymns as well as journal articles and sermons, and an accomplished translator, his books included Joyfully Christian: Truly African and his recent autobiography Fan into Flame. The Daily Nation newspaper of Kenya calls the latter memoir "explosive" and observes that the church leader was never reluctant to apply Christian ethics to politics: "Dr Gatu will be remembered for speaking out against excesses of previous governments, especially that of President Daniel Moi."

John G. Gatu was born on 3 March 1925 in Kiambu, Kenya. He was educated at St Paul's United Theological College, Limuru (1951-55), New College, Edinburgh UK (1958), Pittsburgh Theological Seminary USA (1963) and Princeton Theological Seminary USA (1970-71). His wife, Rahabu Gatu, died in 2016.

Rev. Kiongo was born in 1912. After teaching for more than 16 years , He was ordained in 1953 after three years of theological studies at Fort Hare in South Africa. He was keen in laytraining, church literature and theological education. He was a tu­tor at the P.C.E.A Pastoral Institute. He served the church with vigor, courage and devotion especially durin the time of the infamous oathings of 1969.  He died on Easter Sunday, April 7, 1996. 

He was the first Afri­can Moderator during the church 3rd and 4th General Assemblies.

He was born in 1898, He was involved in translation of the psalms and was named a senior preacher in 1933 after three years sturdy under Rev RGM Calderwood. He was ordained in February 1939. From Feb 1942 - December 1945 he seerved as a chaplain of the army of the Middle East. A highly regarded concillator. Rev. C.M Kareri led the church as it grew into independence with unparalled courage and became an indigenous church with. He loved his church and gave exemplary services to the church and the nation of Kenya. He served the church until his death in 1978.