Mandefro was born to an Orthodox Christian family, attended Christian school, and joined the priesthood. He was one of the clerics fortunate enough to be tutored personally by Emperor Haile Selassie I, the titular head of the Church.
In October 1959, the Ethiopian Orthodox Church officially established a branch in New York; Abba Laike Mandefro, as he was then known, was sent there in 1963 and was given the task of finding a more suitable building for the Church, which was purchased in 1966. Mandefro then returned to Ethiopia to seek assistance for renovations; unfortunately the building was taken by the New York City authorities in his absence.
With the assistance of Emperor Haile Selassie, and the Ethiopian consulate in New York, Mandefro returned to New York City and purchased another site for the Church in 1969.
In 1970, he was sent to Jamaica where he began to minister specifically to the Rastafari community, at the official invitation of Rasta elders including Joseph Hibbert, who was in turn named as a "Spiritual Organizer" by Mandefro. Many government officials and others in Jamaica were deeply disappointed that Abba Mandefro defended the Rastafarians' faith on many occasions, and that he baptised thousands of them, pointedly refusing to denounce their faith in Haile Selassie as the returned Christ. On the other hand, a large number of other Rastas were likewise disappointed because he would not baptise them in the name of the Emperor, but only in the name of Jesus Christ. This however did not disturb those Rastas who viewed Christ and Haile Selassie as one and the same, and readily underwent baptism at the hands of this man who had been sent from Ethiopia by their living God. Only after the Marxist Derg Revolution that toppled Haile Selassie and appointed their own Patriarch over the Church, did the requirement become enforced for prospective baptisees in Jamaica to renounce his divinity and cut their dreadlocks.
Abba Mandefro also founded many Orthodox Churches throughout the Caribbean and elsewhere, and received the title "Archbishop Yesehaq of the Western Hemisphere and South Africa" in 1979. On 4 November 1980, he baptized world-renowned Rastafari musician Bob Marley, then suffering from terminal illness, into the church.
In the 1990s, a schism happened in the Orthodox Church when the new government of the EPRDF took power in Ethiopia and appointed their own Patriarch, Abuna Paulos. Abuna Yesehaq refused to recognise this political change, pointing out that according to the ancient Church canons, the Church leaders are to remain in office until they pass away, and cannot be dismissed or reappointed by any secular government. However, the New York City authorities took the side of the newly appointed Patriarch, and police interrupted a Church service on 9 August 1998 with guns drawn, using profanity, handcuffed children, and took possession of the Church in the name of Abuna Paulos.
- Archbishop Yesehaq. The Ethiopian Tewahedo Church: An Integrally African Church. J.C. Winston Pub. Co., 1997. 244 pp. ISBN 9781555237394
- "About His Eminence, Rasta Bishop" at Abba Yesehaq.com website
- Obituary in NY Times
- Barry Chevannes, "The Apotheosis of Rastafari Heroes", in Religion, Diaspora and Cultural Identity by John W. Pulis, p. 345